You definitely qualify for SSDI and the amount you are getting probably indicates that is what you are getting (I don't think SSI is that much, but unsure).
I have a son with severe autism - so services for children/adults with severe disabilities I am well versed with, and I am highly involved in advocacy work in this field.
I've witnessed a bit of what you go through. I dated a woman with a severely autistic daughter and prior to my medical condition becoming symptomatic, I drove a school bus for autistic children. I understand the challenges that you and other parents of special needs children face every minute of the day.
That's why it pisses me off to no end this government will spend billions importing poverty from the Third World, while native born Americans struggle. I made contributions to the Great Ponzi scheme in the Capitol, so it's not an entitlement. I would have much preferred to have invested my money where I would have made a better return.