Hi Mom of 5,
I am sorry for son's troubles. I hope you can figure out the hs thing. I don't know what state of NY is req to do for children with disabilities. I struggled and failed for mine is MA, but I was fighting for learning disabilities (ADHD and other).
What I will tell you though is, or should I ask, could it also be a little of the age thing? I know once my kids into hs they didn't like school at all, largely cuz it was the cool thing. Once we kept pushing and trying to keep my daughter in the right direction, we found a college that she loves and is totally re-engaged in school.
We also had a struggle since she wasn't diagnosed with ADHD until senior year in hs. We were able but had to pick up the costs of a math tutor who was fantastic. My daughter actually wound up with an A a couple of quarters in calc despite being told this would be a problem course.