Hi and welcome to DWD. My husband has had depression for as long as I have known him, had a couple of breakdowns and been through therapy a couple of times...
He was on the highest dose of Fluoxetine for years but it made him feel nothing and he has changed to Venlafaxine which has been a game changer. You might find that he needs a meds review...
Alcohol is a depressant. Drinking isn't going to make things any better...
Has he thought of trying to get counselling now? What about a support group or something?