I also have a DD 7 who is VERY bright she is a young 2nd grader (just turned 7) their school does their IOWA testing in Sept instead of May. She did very well in LA 99% and reading comp was 98% she reads at a 4-5 grade level. She is NOT gifted she is very bright. You get that when you actually have a HG/PG kid.
Are you making this comparison between your DD and DS based on fitting in socially and behaviorally at school? Because I don't think that should be regarded as a marker of giftedness/intellectual capacity.
Girls often have better fitting-in skills at a younger age; this is not a mark of not being gifted, only shows that your DD is paying attention to norms around her, which is an asset as long as it doesn't make her underperform to fit in with other kids.
I can see that the current school is a terrible fit. Still, your DS probably needs to be taught to recognize the social hierarchies that operate in schools and elsewhere; teachers have a kind of authority that must be respected even when one differs with them. If he is poor at recognizing this kind of social hierarchy, he will constantly be in trouble. (My DS has Asperger's and we have to work on this a lot.)
I hope HSing gives you the respite you need!
DeeDee