Originally Posted by
jseattle 
Unfortunately, I think 20 years of supporting him and them and letting everything fall on me was a big contributor to my alcoholism.
Rather than thinking of it as support, how about acceptance? By that I mean accepting that he's facing a pretty scary proposition with his mother finding out that she's got a deadly disease. Whether she's a good person or not it's a pretty devastating blow to her and certainly her husband and your husband.
Do what you need to do to protect your sobriety first and foremost - go to your IOP, hit a meeting, whatever it takes.