You are being terribly abused. The children are not in a good environment.
No matter what happens you have got to protect and stabilize yourself for your self and for the kids.
You sound like you have the instincts to do the right thing. No matter what, though, you can be of no help to anybody if you go under with Cory.
Get yourself to a safe place,Take care of you. Read up on alcoholism, and abuse, and codependency.. THEN, when you are stronger, and clearer you can get some help to make a plan for how to proceed to get the kids into a better environment.