I am sorry for your situation and I can only speak from the alcoholic side. I did anything I needed to to protect my addiction. Wife, kids, job, health, took second place. There was no low that was too low for me. I was a liar, cheat and thief. There was nothing that anyone could do for me until I decided to change.
Unfotunately many die before they decide to change and that is the ugly truth of addiction. You can be there for him if he wants to get better but until/if that happens you need to take care of yourself and distance him from you and your family.
My wife goes to Alanon and is a big fan. Alanon teaches you how to take care yourself when a loved one is in active addiction or how to pick up the pieces after they sober up