My dad was the same way, except he wasn't recovering and actively drank until the day he died a few months ago. He was just a selfish taker by nature. His second wife was a perfect fit for him. She drank like a fish, smoked like a chimney, and had a really nice well paying job so that she supported my dad and he was able to quit his full time job. I always felt that he took advantage of her but she always told me that she knew what she was getting into with him. I realized early on that it was their marriage and their problems. I worked through my own issues by doing some serious work on forgiveness and I dealt with my own resentment and anger towards my dad. If his wife had issues with him, then she would handle them the way SHE needed to.
Honestly, working through my anger and finding real forgiveness for him really made it easier for me to handle his death last December. I accepted him for who he was, I knew he was never going to change even in his dying days, and I let it go. Now, I just wish I could do this with my husband, LOL!