Cola - I have read all of the posts, on this and the other thread you have going, and you have my sympathy. I agree pretty much with what HK has said above.
That said at some point your DS has to realise, that you are the parent and you are (hopefully) asking him to try his best to get through the year in class. It sounds like he is willing to as well.
Sadly in life we have to, at times follow the lead of people we don't respect - be it an power tripping employer in an entry level job or CEO who has lost his marbles. A sexist/racist university professor or A police officer who has pulled you over for ridiculous reasons but still has the power to arrest you....
I think for your sons sake he needs to learn that at certain times you need to suck it up and get on with it. Yes the teacher is bad, but she will be gone next year. Your son wants to understand the why of everything, and believe me I GET that. I'm certain though that with his intelligence he is capable of understanding the lesson without further explanation and this is rather a personal preference, fingernails on the chalkboard situation for him. We all have these times in life and I think you are so close to the situation that you are missing the big picture.
At this point your child does not need to respect his teacher, he just has to do as he's asked - he needs to respect you.
You have advocated so much against this teacher and made good inroads getting an IEP and some of the school staff on board which is brilliant, the school knows the teacher is not a good fit for your son and therefore if he happens to hand in low scoring work the school will understand - I doubt they are expecting A+ in this situation. I think to encourage your son to continue railing against her is akin to banging his head against a brick wall - you have said you have no other options.
