Is 32 too old to be living at home given my poor finances?

Your parents come first I think, this is obvious. You should do what you can to make sure they are taken care of while pursuing your doctorate degree. I believe you should work towards your dream no matter what, and no matter your situation you should not give up that doctorate if it is truly what you want. Co-habitation with him might be helpful for a time, but if it seems like his dreams are more important than yours and he has treated his family poorly in the scope of his goals it might not be a good idea to get involved. I am just saying this objectively. If you are saving for your doctorate you should make it your utmost priority to complete it, don't let anything get in the way at this point. You are 32. The sooner you obtain your doctorate, the better equipped you will be to help out your family and be on your own doing what you enjoy.