You are not overreacting. Not at all.
And, it's all too typical and too familiar.
Yes, he'll have a very hard time admitting to a problem that he loves to blame others for having. I think they like to point fingers to make themselves feel better. Mine played the "I'm not as bad as so-and-so" game too.
He also, by the way, used mouthwash several times a day until I pointed out that they all have alcohol in them. They truly will do anything to get their fix.
He used to say, "Oh I only had one beer". Well his one beer was really a tall malt liquor, or a pint of whiskey.
I'm afraid it usually gets much much worse before it gets better. They do have to hit their own bottom, and it's typically way lower than you can even imagine.
Have an exit strategy for yourself for this church weekend with no alcohol. Make sure you take care of YOURSELF and your children. Don't try to stop him in his descent, you'll only impede his progress. It HAS to get worse before it can get better.
Keep reading and keep posting! And I'm sorry you're going through this. It stinks.