http://www.hslda.org/strugglinglearner/sn_states.asp

I'm not sure how updated it is so I'd ask your advocate about the specifics and how homeschooling families are actually treated. If your state does not provide SPED services to HS students then you could look into online public school charters. They are obligated to provide SPED services and accommodations.

You might want to ask advocate if there are ways to keep your son at home while sorting out the eligibility issues and upon his return, if his 504 or IEP is not followed, you have additional legal recourses.