Mother in law and alcohol problem?

My mother in law is a very a nice woman and always she has been very nice to me. We leave in different cities but we visit her often. She has been through very tough times since she took a divorce with my father in law. That’s more than 10 years but she seems to not move on. She hasn’t been with any other man, she doesn’t have a stable job neither she has any hobbies. The last two years she has started drinking alcohol (whiskey) in daily basis. She claims she has only one glass every afternoon but I think she is lying. My husband has confronted her for this topic and because she is a heavy smoker. I have seen her mixing whiskey with beer and saying that it’s just beer while we are having lunch. Also once her sister called my husband to tell him that she saw her tipsy in the morning. I don’t want to get very much involved but I don’t know what to do. Soon we will be moving in an other country and I am worried.