Sounds like a complicated matter.
My initial reaction is to just let him compete with the boys. It's what he wants and it would keep things fair for the other people competing. But that would also set a precedent for people in the opposite situation (males transitioning to females) which as a whole is more complicated.
The only solution I see is that rather than having a general rule for all cases you have some sort of board analyse and decide on individual cases like this. But that would introduce its own set of issues
I'm not sure where I personally stand on the matter, but for the sake of discussion, what do you think about the following scenario? -- My friend in high school was diagnosed with juvenile diabetes. He was a scrawny-ass kid. His meds for his diabetes contained steroids and he basically became Captain America overnight. Quarterback of the football team, and broke many state weightlifting records in Florida. He put in some crazy hard work, like an insane amount, but there's no question that the roids helped him along the way. He certainly didn't ask for his diabetes. Should he have been banned from competition?
Not the person you quoted but no, he shouldn't have been allowed to compete.
I'd feel bad for him and I'd never question that he isn't putting in a lot of work but these substances are banned for a reason and it should apply to all cases even if it's being taken for medical reasons.
My friend from high school dreamed about joining the air force, he had the grades, fitness and even the contacts to accomplish it since both his dad and grandpa had served in the air force. But he had to give up on that dream when he found out that his eyesight wasn't good enough. He certainly didn't ask for bad eye sight but simply had to accept that because of an unwanted condition in his body there were things he just wouldn't be able to do.