Addiction can definitely cause bipolar symptoms, especially anger and depression. When I first saw a psych, I had been clean a year and was told that's good, because that would have been the first thing I would have had to tackle to get a true diagnosis for my bipolar 1. Unfortunately, only the addict can decide to quit and do it. Many people have to be in a very low place to quit drugs or alcohol and those who help them have to stop, until they start helping themselves. To enable an addict is the worst thing we can do, but our love for family makes it very difficult. Is he accepting the alcohol is a problem?
Has he been diagnosed because alcohol could be the main issue here.