5LStang,
I agree, call his AA sponsor. My dad has been sober and in AA for 9.5 years. His life partner of 31 years died on the 7th of January this year. I've been worried about a relapse. He's still attending meetings and so far, so good, although he's in a very hard place right now. I'm the only person in our direct family he talks to about his alcoholism. I have told him that should he relapse, I'll be organising an intervention whether he likes it or not. (he too has medical problems and if he drank, it could kill him). He laughed, when I said it, but he also knows I mean it. It's too much on your shoulders and your brother's shoulders to take this burden on your own and his sponsor may be hard but right now, that's what your dad needs...