If you don't feel you can control the urge with that many people drinking, then it is best to stay away as everyone else has said. However, I would talk to my Dad and tell him that you want to see him soon but that it needs to be with no alcohol present. I am sure your family wouldn't mind a get together for you involving no alcohol. You could also try to get there before the drinking started, or planning with your Dad how you could stay a while before they started to drink. That really is your best bet. It's the same with everything else. We can control the urges ourselves, but we can't control them if we don't truly believe in our minds that we can. We have to tell ourselves we are going to control them and actually believe it. Until you're there, it's best to stay away.