
That is tough. It's wonderful that you're so active in advocating for them with their schools, and unfortunate that they're not being very supportive.
Your older one sounds like my brother in high school - wouldn't accept that he's different from the type of people the system was designed for, wouldn't willingly accept help, and wouldn't accept the evidence that he couldn't get it done on his own.

He also allowed ill-informed, judgemental teachers (many of whom he was probably more intelligent than) to make him feel bad about things that there was no need to feel bad about. I hope your son can achieve a better understanding of himself and become more educated about how his brain works than my brother did in HS; it will make things easier on both of you.