Can dd go live with her mother or another relative for awhile (and then stay with his mother when you all move out)? Sounds like with the crowded housing getting rid of some of the roommates for a bit would help everyone!

I would move into the house you have to pay for until they re-rent it and see if you maybe can figure out how to do work from elsewhere (his mother's duplex?). Maybe you can exchange services for rent with a friend or other relative or other busines not in that city with the laws?