In all fairness, she didn't. Her parents moved her out of their house. Not exactly the same thing. She can't even pick up her fucking heartburn medication herself, her cancer-ridden mother has to do it. The only way she would end up maintaining a regimen of testosterone regardless of dosage form is if one of her parents were the ones monitoring her schedule and supply, calling the pharmacy in advance of running out, making a doctors' appointment in advance of when the last refill is about to run out, picking up refills on the correct day (it is a controlled substance so there are rules here), possibly purchasing the correct injection supplies or taking care of copays, calling the insurance company to hash out any discrepancies with coverage (which happen all the time for retarded reasons), etc. Without them doing even this very minimal legwork, it won't happen, and they know this, which is why they are so completely unconcerned. They've been listening her go on at length for a decade about how she is a total for real actual gay/trans & inventing nonsense definitions to claim she's in any way LGBT - regardless of how well they understand the queer stuff, Stephanie's idea of it makes literally no sense, so nodding and agreeing when Staph goes on about how "potato salad is a gender, that's what this flag means" is par for the course. It says a lot that even her grandpa's attitude is more or less what the fuck ever.
Basically, it's hard to have a big dramatic "coming out as a tranny" bombshell moment with the drama she was going for when she's been blathering about tranny faggot stuff daily for so long it's become literal background noise. They know to pick their battles, especially when arguing with a retard. If they'd prefer she not fuck herself up worse with hormones, they don't even need to say that and deal with the tantrum, they just have to say "it's your responsibility" and that's pretty much the end of that right there.
Now let's count down to the inevitable Gofundme because she has a copay and doesn't want to spend her allocated pins-and-scams money on her "medically necessary" hormones...