I have a hard time believing that a high school director would give their student Rach 3 to play.. To me this band director sounds reckless and irresponsible.. If i was a band director i would not give a piece that big to their 8th grade students, no matter how talented they are, because its way beyond the scope of things I can teach. how can a band director give something challenging without assessing the risk? he might be putting his students through a lot of frustration, and even injury.
Not just that, if I was a band director, I would talk to you immediately and strongly urge you to send your son to music school..or study with the top pianists you can find, because he has an exceptional talent. I am surprised that nobody who has heard your son play has done the same, because a talent like that would be too obvious to ignore..
If i was a parent, i wouldn't want to push my kids too hard either, but if your kid really has that much talent, if he is the next mozart, it's my responsibility to make sure i find someone who can nurture his talent.. i will find an expert, the best teacher available, or i will find someone who knows someone.. i'll do whatever i can do to get him exposed to the best education.. arrange meeting with teachers..and let my kid know that he has a rare gift, and tell him that whatever education he needs is available for him.. i dont think i would be a good parent if i did anything less than that.