>can’t legally drink a beer but can take gender-altering
>drugs. And apparently he started this in 2015.

Children take all kinda of medications and "drugs" at many different ages, administered by trained professionals and with parental consent.

What this has to do with recreational drug use is anyone's guess.

>
>I have no problem with people being whoever they want to be
>but should these decisions be made at 15-16 years old?


This is a question for the parents and doctors involved. I suspect you don't know anything about the subject that they do not.