I've hesitated to write this, because... well, because I'm old enough to know people won't ever listen to what they don't want to hear.
But I'm also young enough to be bold anyway, and - unlike so many online-only "trans" people, I actually give a shit about people being used, conned, & hurt.
TheymerSophie (Twitter), Curio (YouTube), Eric Sophie McAllister... is NOT who they say they are. Their story isn't the one they're telling you.
. They did NOT start on estrogen in June 2020. For most of 2020, gender clinics (a mandatory part of transition in the UK) weren't even seeing CURRENT patients for next-step transition treatment, much less people who, as late as January 2020, were musing around "possibly" being non-binary.
. Their relationship with their sister? Is one that involved them threatening her with a knife, repeated gaslighting her, deliberately causing trouble for her when neurodiversities (and their failure to be contactable) meant she returned home "without consulting anyone" when their mother was in hospital - she is medically banned from driving, feels unsafe travelling after dark, and had to travel back to Lowestoft from Cambridge by train. Her sibling COULD have phoned HER to find out what was happening - instead, they phoned their elder brother, who then phoned their sister, was aggressive to her, and misgendered her. (Their sister, incidentally, IS a trans woman.)
According to TheymerSophie, sorting ID documents is "a nightmare." It really isn't, IF you have a Deed Poll, which clinics in the UK will require before accepting you as a patient. I had absolutely zero problems getting ID changed in a rural market town in 2008 - they live in London. It's 2021. (Incidentally, their sister had no problems sorting ID documents, including formal things like the Visual Impairment Register, bank account, registering with the DWP, either...) Curios/TheymerSophie/Eric McAllister's sister is my wife. Our house is in my (legal, male) name; that was precisely zero hassle, because I had my documents sorted, even though the current system for gender recognition means I can't change my birth certificate. I've even got a DBS (Disclosure and Barring Service) Enhanced report in the name and gender I live and am known by.
ALL of the "I'm trans now!" started IMMEDIATELY after their sister spent a night at theirs. Tellingly, she was performing in a Queer Women comedy line up - TheymerSophie was invited to come along, but refused. (Unusual, surely, for someone who was SO into exploring their own gender identity in January 2020?)
They have previously claimed to be on estrogen that they have been prescribed, but completely freaked out when it was mooted that estrogen become a controlled substance, literally talking about how they'd "have to leave the country" - testosterone has ALWAYS been a controlled substance, in the time I've been taking it; getting my 'script approved was never a problem; the worst that happened was a couple of times there were supply chain issues which caused delays.
My wife literally grew up with this person. She doesn't lie, and therefore I believe and trust her when she tells me they were arrogant, aggressive, violent, and manipulative right into early adulthood, during which entire time they showed no signs of discomfort with their body, or with living in a male role.
TheymerSophie viciously, verbally attacked their sister for shaving her arms, and routinely mocked her for "acting like a girl." When their sister came out to their mother, her response was "How could you do this to Eric? Think about how this will affect (him)." At NO. POINT. did they step in, & tell their mother they didn't have a problem with having a trans sibling.
If you follow TheymerSophie (Twitter) or Curio (YouTube) - ask them who their consulting psychiatrist for transition is. Ask them what dose of estrogen they're on. Ask them which clinic they're attending, and how often they're seen - yes, people DO DIY transition (my wife is doing so, because finances and disability make it very challenging for her to get to London as regularly as Charing Cross require), but they have previously been VERY scathing about DIY hormones. (Which have given their sister a full cup size increase in breast size, more prominent and tender nipples, and more curves around the hips, in just under 8mths since she began taking herbal estrogen supplements, and just under 6mths since she began taking herbal progesterone.) Ask them why, if being trans makes them so happy & fulfilled, they need to smoke cannabis practically all the time? (People who use it medicinally, for religious reasons, or as an occasional thing, not a problem - when you are literally all over Twitter, all the time, bragging about getting high... you're an addict. And people become addicts because something has gone badly wrong in their lives, & nothing else they do can fix it.) Ask them, since they have apparently come out to their mother, she still refers to them - in emails to my wife, whose name she uses, & who has mentioned being on hormones - as "he." (Following ovo-hysterectomy in 2011, I stopped taking testosterone in 2013, and now simply take herbal testosterone supplements whenever I feel I need to; however, my dose of Nebido was 1000mg by intramuscular injection every 3mths. I was seen by James Barrett primarily at Charing Cross, with Andrew Davis providing the second opinion consultation. Just to prove that those of us who aren't inventing a life actually KNOW this stuff, & remember it years later - my first shot of Nebido was at 10.54am on the 18th December 2008; I'd legally changed my name 3yrs and 9 days before that, and 18mths before I was even referred to Charing Cross. Within 2wks of changing my name, ALL my documents were changed as well.)
Ask them why they act as though they're the only "trans woman" in Southwark - I live in Lowestoft, and know of three trans women other than my wife, and several femme-spec non-binary people, as well as another trans man. I wasn't even the only trans person in the very rural village I come from - it's highly unlikely there are no other trans women in Southwark, but quite telling that Curio thinks they're unique.
Ask them why they've only EVER contacted their sister to either manipulate or gaslight her, or when they want something. Ask them why they refused to give her their address so she could send a Christmas card. Ask them why they went into a complete fit about how she had "been deliberately cruel and vindictive" when she wrote a letter to them in response to communication from them that had triggered her, explaining her feelings, and why the communication had been problematic for her.
Ask them, finally, why none of their work profiles (eg, LinkedIn) have been changed/deleted. I have literally never HAD a social profile in my previous name.
@HowUnseelieOfMe (Twitter) is their sister, my wife, and a woman who is getting on and living her life AS a woman, without expecting to be showered with gifts, applause, and money for "being trans." She knows a lot about haircare and cosmetology, is an excellent intuitive tarot reader and genuine psychic medium, can discourse very intelligently on a great many subjects, and has a quirky sense of observational humour that she's currently trying to figure out how to get into stand up with, considering she's legally blind, and literally broke, so travelling the circuit is a bit challenging. (I'm also visually impaired, and equally under-employed, so can't really help.)
Below are several photos of @HowUnseelieOfMe (my wife, TheymerSophie/Curio's sister). No filters (neither of us have smartphones), standard lighting, minimal makeup, no editing:
Comparisons in transition: The photo on the left was taken in 2014, about 6mths after @HowUnseelieOfMe had begun social transition. 
Photo taken summer 2021.
This photo was taken early in 2021.
No, not everyone's transition looks the same, not everyone gets the same results.
But some people lie, for reasons of their own, and particularly when something (like being trans) is seen as "freaky & interesting", and other people are getting money because they happen to be trans. (But, importantly, also actually DO THINGS in the real world - they don't just pontificate and snipe at people on Twitter.)
Bear in mind, @HowUnseelieOfMe has been referred, by Ted Olive of Town Close Clinic, Norwich to Charing Cross Gender Identity Clinic, London (in 2013), but has NOT been able to attend, owing to financial & logistical challenges (if anyone would like to help her overcome the financial challenges, her PayPal is [email protected], which can also be used to drop her a note if you want to book a tarot reading, or commission writing on autism, ADHD, trans experience, psychic stuff, magickal myths and history, and practical, inclusive, intersectional femininsm. Or, indeed, book her for comedy gigs in Norwich, Lowestoft, and surrounding areas.
Stop falling for the cute and clueless who never bring anything other than some half-baked "identity" to the table.
Follow, support, and help trans and non-binary people who are just trying to get on and live ordinary lives as their genders - which is the entire POINT of transitioning, whatever way and however far someone chooses to take that; that you get to be ordinary, and just live.
I am aware I won't be believed.
I am aware people are going to be angry.
I'm also aware that truth matters more than someone else's reaction to it.
And if the individual in question wants to respond? They have their sister's email - she's the one who deserves communication, answers, and several apologies. Just know that she WILL show me that email, as and when it arrives, and my entire focus is protecting and defending her - and I'm FAR too old to be scared of someone who has to invent a life for bloody Twitter.