That's awful. I'm so sorry, It's one thing having this happen after you've lived a bit but you've barely gotten past your teens and been saddled with more than most of us will ever understand.
My kids are sen, being assessed and it looks like adhd, asd, dyspraxia and dyslexia type issues. Which has been hard, but what you're going through is my worst nightmare.
I felt that was me, now. I'm disabled and have mostly raised the kids on my own. I've only recently moved back nearer my parents as they're both retired now. The relationship isn't great but it's already helping. Before then, the isolation was chronic. Deafening silence in the 'living' dept.
Living in a smaller community can help a lot more. But before you look at house swaps etc, really look into the kinds of health care and policies on whatever therapy your kid needs, for that area. It's only since we've moved that my kids are being picked up for their issues which I had given up telling their previous schools and GPs about.
You don't want to move somewhere and be stiffed for support or therapy.
Have a Google (or ask at whatever clinic you may be attending) for any social groups for your little one, as you may be able to meet some other parents through that. Which means you may eventually be able to babysit for each other sometimes.
I think knowing more people with an understanding of whatever your kid has, would be beneficial.
I hope things improve.