It seems he is doing all the classic self-denial tricks like setting rules around his drinking to prove to everyone, including himself, how in-control he is. Every time you challenge him he is affronted, and now he is trying to suggest that you are a hypocrite because of your weight gain. The lockdown makes all this far worse.
You might consider trying a counter-intuitive approach by asking him if he would like to explore ways he could enjoy and control his drinking better, rather than persuade him to cut down or quit (the dependent drinker’s biggest fear). You might find notalcoholicbut.com helpful in this regard. At least it will show your support for his continued drinking whilst giving him the space to self-analyse what he is actually getting from alcohol – which of course is not a lot. Worth a try perhaps?