Dear Paulakea,
The Jekyll and Hyde of this man's personality is no accident.
He is a MASTER MANIPULATOR.
And the brother/sister-in-law/child "issue" is further indicative of just how screwed up he really is.
The man is a SNAKE! Your friends are right. Run, don't walk, away from this man!
You may have to get together with your Mom, on a pretext of a visit, or dinner, or whatever and find a place of your own behind his back. And like another friend mentioned, start getting rid of stuff little by little. (Start with the most important -- identity papers, social security, pay stubs, family photos, sentimental gifts from family and best friends, etc., things you can't replace. That having been said, keep in mind that In the end, you may not be able to afford a smooth exit, but at this point an exit is crucial. This man will drive you insane if you stay.
Remember, Mr. Master Manipulator is holding your financial hardship situation over you. It is a large contributor to his abillity to have COMPLETE CONTROL. You have no need to feel sorry for this man -- he is quite cunning. His tearful sorrys are just crococile tears. They are fake. He is very, very good at what he does. Know this.
All these things that we are saying to you are true. You need to set yourself free. Please do this for yourself.
Sincerely,
...foreverlove