Sorry to hear that you are going through this
It's hard to enough to take care of kids when they are healthy, it sounds like you've got burdens to deal with on multiple fronts.
Are you in the US? Canada? If so, you could call 211 or visit
www.211.org
I'm not sure they could help, but maybe. You might be able to get a visiting nurse or have some other healthcare options available to you because of your son's disability.