It's easy to fall in love with our own hopeful fantasies of who we need/want in our lives. "Out of Hope" often means the begining of the reconcilliation between hopeful fantasies and realitiy.
You did not cause this.
You cannot control this.
You cannot cure this.
Only he can decide to change his life. Nothing you say or do is going to get or keep him sober. You are not that powerful. None of us are.
Only you can decide to save yourself or allow yourself to be dragged down by him.