Thank you all so much for your wonderful insight!
You're right. While my wife and I have never had a point-blank conversation about her drinking and its impact, she drinks and gets drunk in front of all of us so that is all 'old' information.
I plan on talking with my son this weekend about what he's experiencing and how he feels about it. I'll make sure that he knows that her drinking is not his fault and certainly not his responsibility.
Hopefully, he can learn to concentrate on himself and realize that, like me, his words can't change her.
I don't want denial to rule our home. I want him to know that I'm here for him.