I'm guessing your past this option but you could try a Montessori classroom -- less structured and allows children to chase their own pursuits. My sense is its stronger for years 1-6 as opposed to later years. Also it doesn't feel like Montessori tries to grind down the children - school/teachers dependent for sure (same could be said for other systems).
Oh he's well past that now. He did graduate High School, kept his grades up enough to be eligible to participate in some extracurriculars that he enjoyed. He made a couple attempts at community college, but it didn't go well and we agreed that we'd stop wasting money on that for now.