The young person with the alcoholic father should contact Alateen.org himself and get some advice about how to live with an alcoholic parent. His mother can get information from Alcohol Anonymous and even attend meetings for spouses. They'll learn facts and may find a way to talk with the father to make him hear what they are saying or, at least, stop abetting the disease, which we in the family are doing without realizing it. It would be terrible to learn the facts after the father has lost his job and gone farther down hill.
As for having your father "give you away," my husband asked for my father's permission to marry me and Dad walked me down the aisle. Of course, this wasn't necessary and we all understood this, but customs are there for the purpose of making connections within the family. I'm smiling because I've heard her arguments before and even thought them myself but found myself enjoying the memory of having my Dad there for that walk. When it came time to marry again, my new husband asked Dad, too. I didn't realize he was going to do that. I was a fully emancipated, 25 year old divorced woman, but it was a sweet gesture. After all, this person they didn't know well was going to live with their daughter for the rest of her life. It was nice to let the father consider this and talk man-to-man for a few moments and for the groom to realize he was entering a family as well as getting married.