at the cusp of puberty he was put on hormone blockers and height blockers as well as estrogen.

Since he's 6'3 or 190.5 cm, the height blockers clearly didn't work. Which brings up an interesting point: from what I've read of the little research there is out there, it seems (some) boys put on puberty blockers as part of medical "transition" might actually end up taller than they otherwise would have been. Whereas girls put on blockers end up shorter than they would've been naturally.

This different effects that puberty blockers have on the two sexes probably is due to a fact that keeps getting obscured and left out of the discussions of puberty blocker use for youngsters who ID as "trans": female and male puberty are very different in myriad ways.

Many of the ways in which female puberty is different to male puberty still aren't understood, or even recognized, coz of longstanding sexism in medical research and thinking as well as amongst the general public and gender identity ideologues. It's widely but mistakenly assumed that males are the default humans representing the norm, so anything that occurs in and is true of males during puberty must also happen in and apply to females in puberty.

But one thing that long has been known and recognized is that female humans on average start puberty at least a year earlier than males, and girls have the big growth spurt that occurs in puberty at the start of it. Whereas boys have their pubertal growth spurt at the end of puberty, or after puberty is all over. Girls typically reach adult height between 12 and 14. But boys don't reach their adult height until 16 on average - and in many cases, not until 18.