Personally I'd get him arrested for drugs, get a restraining order, and get him the hell out of there come what may. You can't keep going on like that and you cannot allow him to abuse your child any longer.
I am sure you worked hard for your RE license, but imo you are going to have find another job and do RE on the side for now. You must be pretty smart to have gotten your license - you can certainly find an office job that will help you stand alone. Rent out part of the house, sell things, clean houses on the weekend. What hell of financial malestrom could possibly be worse than how you are living?
And next time he tries to kick you out of the den challenge him to make you move. I hope he starts pushing you around and you can get him arrested and get an order of protection. What a stinkin *****.