Does your father hide his drinking? Is that why your Mom had to tell you? Or had you just kind of accepted it as normal? You might learn a lot by reading around on the internet in literature for adult children of alcoholics. I have found material on the roles that children take on in alcoholic families especially interesting. Might help you to understand the dynamics of your family. It does sound like it might be easier to let your brother do what he's doing without getting super involved, but I do think it's good for you to start actively thinking about what your father's alcoholism means to you. One thing I think that children of alcoholics sometimes have problems with is trusting their guts--at least I know I did. When there is so much secrecy in a family and problems aren't openly discussed, we start to not believe it when our instincts tell us something is wrong, and we start to try to accept unacceptable behavior. It sounds like your gut is telling you this new guy isn't a worthy suitor. I think you should trust yourself on that.