Here's an idea for math--
If he works problem sets/assignments backwards-- that is, starting with the most challenging problems he's been assigned, and only doing the "easy" ones if he gets the hard ones wrong.
That way he'll have greater incentive to write out work on just one or two problems... and if he gets those RIGHT, then everyone is happy with his demonstration of mastery.
Assuming that he will agree to "write everything out" for the first one or two.
This is a strategy that we implemented with DD-- if the problems weren't hard enough she would refuse to write out steps, and if she got them wrong, then it was a total mystery WHY, too. Useless all around, actually. Harder problems FIRST solved that, plus she had the incentive of not being bored or forced to do more writing if she did the hard ones right-- and truthfully, they were more appropriate anyway.
Your teacher sounds great, so it could be that this person would be willing to TRY that approach and see if it is something that could go in as an IEP line item.
