But the money wouldn't be coming from the AAU coach would it?
Not from him - to him. From shoe companies (and colleges). I know of a guy here in the Carolinas whose primary source of income is payola for directing his players to specific coaches/schools. Coaches have always had a huge impact on where a player gets directed (read Game Changer re: Charlie Scott), the more the money gets involved, the more impact - especially with kids that do not have the strong, stable family structure that your son has.
It is interesting, I was reading back through the thread re: Tariq Owens and his departure from Ohio (heavily influenced by his AAU coach - led to a Twitter tiff between the coach and Bobcat Love). At issue was whether we should let Owens out of his LOI. General take was that the kid commits to the school, not the coach - appears they are now starting by considering the shoe partner. Not because of an allegiance to a "brand" or podiatry fit, but because. as always, one must follow the money.