Seriously, walk away. Forget all of them.
You have no idea what lies he told them to hide or excuse his alcoholism. I know. I did the same thing when my wife left me. I told my parents anything I could to make her the bad guy. Now she was by no means innocent in it all, but I absolutely hid my drinking problem from family. It wasn't until 5 years later, when I was desperate for help that I told my parents the truth.
Just chock it all up to alcoholic behavior. Move on and up. You'll thank yourself later.