I'll try to offer something slightly different.
I've noticed since the covid pandemic that my drinking can turn into a downward spiral. During the pandemic, I was bored and stuck in the house all day so I started in on my stash of beers.
I was slower getting up the next day and didn't really do anything because I had those beers the night before. And since I was inside again, bored all day and not really motivated to do anything else, I would open the fridge and started grabbing beers.
Rinse, repeat.
Just before the lockdowns ended here I pulled myself out of the cycle by forcing my butt to go out to the garage at 4am. Luckily Mrs. Hungary isn't one to put up with my crap so when my alarm when off and I didn't get up, she smacked me upside the head and kicked me out of the bedroom for disturbing her at such a stupid hour. All I did that morning was stare at my mess of a workbench, and try to clear the fog in my head. I think I might have put a tool or two away...
But I did it again the next day, and the next, and pretty soon I wasn't sitting around the house all day doing nothin but drinking.
So I was going to ask: "can you distract him a bit?"
Can you take him out and do something. It doesn't have to be anything big, or regular, it could just be something casual. Get him out of the house for that endorphin hit, and maybe it'll lessen the desire to drink?
Or maybe it will just lessen the time he has available to drink.
A simple "No. We're go-carting right now. You can have your beer when you get home or somethin', but right now I'm kickin your ass on the track and I want you sober for it so you can take notes"
I'll say this. I still drink (and don't plan to ever stop completely). But hitting that downward spiral was a huge shock to me, and I can 100% see how people get stuck in it. Getting out of it was damn tough. I'm not usually prone to depression, and I didn't like experiencing it one bit. Now that I've been in the thick of it, I can see the warning signs a long ways off (read: before they become a problem) and I steer FAR clear. Even if he doesn't 100% sober up, there's nothin sayin he wont be a million times better off because you got him out of the house and doing something.