Welcome!
I would look at the Special Education Archives on this forum. There are a lot of great threads on dealing with the school district.
Before offering any advice, I have a few questions:
1. What happened on the higher dose of Dextrana that the teacher objected to?
2. Why, specifically, does the teacher think he needs to be held back? Is it because he doesn't complete the work in class for her, because he can't complete the work for you or her, is socially immature?
3. Does he have an IEP?
I'm very impressed that you can get as much studying out of him as you do. If I get 10 minutes a couple times a week out of my boys, we've had a great week.
