Just be honest with him, don’t raise your voice and stand your ground on the topic. Having served, I have seen men change into total pieces of shit because of their buddies influence and their choice of coping mechanisms. I’ve also seen these guys get kicked out and or put into jail for a short time- so that’s up to you whether you wanna take that risk with him. He harshly raised his voice at you while drunk and if he’s got an alcohol problem, imagine how awful he could get. I’d call the wedding off as you seem to have concluded that you’re ok with doing it, just because you deserve better. Show him you don’t need him to pay the rent. Fuck that dude