Jack, I don't have much to add beyond what others have written, but look at the macro picture. YOU don't want to drink. Why should you care what this other person wants? Would you shoot heroin into your veins because he wants you to? You would go over Niagara Falls in barrel because he wants you to? No and no. Be as polite or as aggressive as you want, but this person doesn't have the power to make decisions for you and if he doesn't care what you think about this or any other subject then he's really not a friend.
I'm no longer drinking is all you have to say.