I wish you the best. I will talk with my highschool coaches and ask them if they know of a good leg camp.
The reason I asked is I teach legs to my youth, as I was a legrider. However there is only a select few that we teach until they learn great hips first we do not teach them. Make sure your son knows to as my coach always said "pee on the mat". Once he learns that, just start having him start with a leg in during practice and make sure he keeps tight to the bottom mans hip and let him roll around.