I to was a very very late bloomer. I looked like a little blond girl when I was a freshman. Secondly it sounds like your worried about this and also quetion his nutrition?
You should definetly be "making sure" that hes getting the right nutrition regardless. I used to kick and screem about what I ate but I eventually got into it twards the end of highschool....And i'm proud I did.
Also a Dr. Is alwasy a good idea. ^_^