Happily:
There is absolutely NO reason he has to do inappropriate homework. I would send it back with a note explaining that it was an inappropriate assignment given his disabilities. They can modify it appropriately or they can excuse him from the assignment. Period. You do not have to be compliant.
Please let him benefit from my DD's experience - do not allow him to get to his breaking point. If you are comfortable sending him back to school while you try to work it out with the psych then try to give him parameters. i.e. If your hand starts to hurt I want you to stop writing. Don't worry about having your color changed - you are not going to be in any trouble. Just tell me about it when you come home for lunch and I will take care of it. Just do your best and don't worry about getting in any trouble.
If you send the homework in undone, perhaps along with a note asking the teacher to call you *immediately* if your DS does anything that does not meet with her approval you will be making clear that you WILL be involved. If despite this he is still pushed beyond what his disability will allow, penalized for his disability or otherwise treated in what you consider an inappropriate manner then pull him. You may need an advocate or lawyer or the district may blink and step in. Your magic words will likely be "Americans with Disabilities Act." At this point that will probably have more weight than FAPE, IDEA, etc.
MoN takes a much more conciliatory approach in these matters than I do. If she is saying that she would have pulled her own child in these circumstances I would take that very seriously. She is very, very wise in how she handles these situations.
