I'm very sorry for the situation. We deal with something very similar but are making some headway with DS (almost 11.)
We have stopped trying to get big changes and are working on smaller baby steps. For instance, DS gets to test ahead in math when he gets 3 perfect test scores in a row. I hate that it has to be perfect scores but at least they aren't mandating 100% on the entire curriculmn. Doing this has let DS compact more than a school year into 4 months. Like Dottie's son, ours makes more errors on the easy stuff than something that makes him stop and think.
For those of you in the education field, how much time either in college or in in-service or continuing Ed training is spent on how gifted can present and ways to meet the needs of gifted students? I ask because we had a really illuminating discussion with DS's teacher in the Fall. She really didn't seem to understand the difference between gifted and teacher pleasing high achieving students. Add in the 2E issues and we all began to understand why things could get derailed very quickly.