Sorry and don't mean to be rude--just blunt: a life built on transitory sports glory dreams is going to be full of disappointment and regrets ever after, even for some of the lucky few who get to the medaling level.

Sports for the physical and mental joy of using one's instrument at its best-achievable level as self-perceived is one thing. Setting everything on being accepted to a team leads to sublimation of the individual to conforming to authority, no matter how foolish or vile. See: Olympic women's gymnastics. You need to help your son see beyond the college years and imagine a sustainable lifelong future.