I offer no advise, other than I feel for you. I've worked in a Group Home in the past, with a person who had Bipolar Disorder. It is a very tough thing to deal with, not knowing 'which person' you are going to be dealing with that day. Tread carefully...
The family situation you outlined is just plain disgusting, but is par for the course these days. The decline in morality, the over reliance on the government, and the inability to pick yourself up and move on is quite sad.