I strongly suggest you start getting out of that house on a daily basis. The first place I would go is the first Al-Anon meeting I could find. Second, I'd get a job, any job, even if it's volunteer, to get myself on a predictable routine and away from the insanity you call your husband.
What you describe is a man on a downward spiral, WAY out of control. Wanting him to return to who he used to be (which we ALL have done is understandable but not realistic. Going to Al-Anon and continuing to post and read here will help you get to the place where you can see and accept him for who and what he is right now. The person he is, is NOT the person you remember and love. The person he is, is that person AND the person you are living with right now. They are one and the same.
Focusing on the "good" one is going to get you hurt. You're already a nervous wreck, living in fear, taking pills to help yourself cope with this. This is not good. Think of it this way: This man is out in the middle of the ocean, thrashing about, drowning, and you are out there with him thinking you can help or save him. YOU CAN'T and he is going to drown you. Everytime he starts to sink, he grabs your leg and pulls you under with him. This is a fight and the sooner you realize this, the better. A fight for your life. Who are you going to save? Him? Or you?