I would suggest being sensitive to his attention spans and his wants, as he grows and sees more of what's available to him.
Youngsters have a way of wanting to be a ballplayer today, fireman tomorrow, a cowboy Tuesday and so on. Besides, games are games, all designed to be really fun. Take the fun out of it and his desires become your desires. On the other hand your wording in your posting seems to be aware of that.
If your son has "it", on his own and really takes to the game, especially pitching, he'll do things well enough to draw attention from those that'll want his services. Couple that with his desires to improve and take fun to a new level is the real trick. Youngsters that seem to gravitate to this sport and pitch have always seemed to be moving in that direction, with and without ... "here, let me help you.." kind of thing. All of that will come his way because, again, somebody will want his talent to do something for them ... whoever "them" happen to be.
In addition, helping your son to do things right so he not only enjoys the game, but does so in a healthy way is what your maturity and experience does, and that comes in real handy.