Why don't you call your local DV shelter? They have tons of resources that can guide you, and you can certainly do that without committing to anything - hell, you can usually stay anonymous. Certainly sounds like "power and control" which is at the core of domestic violence... financial abuse is a HUGE deal, and one that often flies under the radar.
Also, blood is thicker than water. Your family may very well circle the proverbial wagons around you, and it sounds like you have a lot more resources than he does. Mine would have if I'd asked. (I didn't need to - my A was never abusive, but sounds like you've got quite the paranoid psycho on your hands.)
Good luck,
D