Behold the mighty Wizard of Oz!!! I know, I know, I wish I were that great, too.
Hold your head up, sweetheart. He says he's quitting then it's all your fault. He says he can have just beer and that doesn't work out so that's your fault.
I have been down that road time and time again. I have made suggestions and tried to help only to be made out as the mighty wizard who made his life hell when his binges only got worse.
Now when my ABF makes proclimations of moderating his drinking, quitting all together, or switching to a certain (disliked) brew to wean himself off it over time, I give him the most sincere smile I can fake (since I know better now) and say, "Good luck with that dear." He has stopped verbally laying blame on me. I'm sure he still stews over how it's all my fault when he's drinking every night, but that's his problem.
I agree with the other posts. Don't engage. In his mind, that would only show your guilt over your wrongdoing.