He's 22 now and living the idle life of a student, Tufty! His problem was severe uncontrollable asthma (to which he added crippling migraines from the age of 11, although that wasn't part of his special needs). But the asthma abated considerably when he was almost 18 and he has been able to live a normal life since then, although I doubt he would ever get accepted into any job where health was of the utmost importance, such as the Forces (not that I'd want him to join up, anyway).
He spent six months working in rural India, post school, which was very worrying, but the air seemed to suit him and he flourished. After that, he held down a f/t office job with no problems and has put his childhood illness behind him.
But there have been lasting effects in that he lacked any confidence. If you can't rely on your own body its a real b*mmer! And as parents we are paying the price in some respects, because now that he has more self esteem he resents us being involved in his life on anything more than a superficial level. Having once been so dependent on us for everything, it's as though he wants to break the shackles that bound him to us. But hey, that's okay! At times we wondered whether whether we would ever see him grow up to manhood, and it's a tiny price to pay for his good health!
I wouldn't worry too much about the future, so much time and so many things will happen between now and then, it's not worth losing sleep and brain cells over.