I think you're a saint to take on your ex's care under such difficult circumstances. Sabby had many good questions&suggestions. Has your ex ever applied for disability? That could help with expenses.
Yes, definitely be thankful that your ex is a non-violent schizophrenic. He's fortunate to have family that cares enough to take on what he can't-his health care. I also think that your son is expecting an awful lot from you-sure he's providing financial support, but he's not going to be dealing with the day to day stuff. I'd look into some support groups for yourself as a caretaker once you get moved. Best of wishes-hugs