If he falls over and pisses himself, he has a big problem with the bottle.
I have been quite a heavy drinker in times of stress and feeling down, the alcohol becomes a crutch, but I would rarely get drunk. 3 cans and fall asleep infront of the TV was my usual style, but often 5 or 6 nights a week, maybe 7 sometimes.
I've cut my drinking down recently, and the first couple of weeks were very difficult to stay away from it, but I'm now only drinking 1-3 times a week and hope to get down to only social occasions out and about and no more than once a week alone, which is how I used to be.
This man sounds like he has a greater problem than I did as mine never persisted for 4+ years or resulted in bed wetting. He needs to take drastic action or there is a risk this will spiral really out of hand. You can't help him directly, he can only help himself.
People can sort out problem drinking, but they have to really want to.
If you want it to work then I think you need to give him an ultimatum, not for immediate action, he will need to reflect on it, and gather mental strength, but I would tell him if he hasn't started to take action to reduce the level and frequency of his drinking within 3 months, then you are going to have to seperate. I would also tell him you will support him im some ways such as going for a walk together in the evening which is free and I find, a good distraction from the "routine" of drinking. If he cannot take that on board and deal with it then his relationship with alcohol is more important than his relationship with you, and then needs to end.
I have a friend who was a much more problematic heavy drinker than me - he would frequently down 8 cans of strong lager every night, drink in the afternoon on every day he wasn't working and so on. He sorted himself out, with exercise and taking up cookery! His marriage had been on the rocks but they now seem very happy. It can be done.