Dear Prudence, 
My adult son is in a relationship with an alcoholic (his word, not mine).  They work different shifts. He has come home from work and found her drunk in the bathtub and then they both wind up yelling. That is just one of many, many situations. I love him very much and have told him that I will always be here for him. He realized two years ago that alcohol was keeping him from truly being “present” in life and, as far as I know, has maintained his sobriety. As much as I want to tell him what to do, I understand I can’t.  This is his relationship, not mine. Therefore it’s really none of my business.
However, the holidays are creeping up on us. My family has plans for everyone to gather at the beach for Thanksgiving. These plans have been in place for a year and it will be the first time in several years we have all been together since we live all across the country. Is there a polite way to tell him that there will be no alcohol or do I need to accept that she will drink and may cause a scene (or two)?
—Not the Girlfriend’s Keeper