In regards to having DH on board. Maybe you could just ask DS to complain only to DH from now on? Have DH go to the conferences and listen to the teacher droll on about how the spaces between words are too small....travesty! Have DH volunteer in the classroom, etc.

Also, you don't have to use a standard curriculum. There are tons of resources available to put together a very individualized curriculum of your own. That's the best part of working with your children at home, IMO.