Why Drink around the Holidays??
Drinking during the holidays can get out of control and create many problems for families, especially in families where problem drinkers are in denial and do nothing to prevent getting intoxicated.
The best advice is to make sure that when you visit, you have a way of escape. Even if your siblings offer to let you stay at their homes, reserve a room at a hotel. That way, if their behavior becomes problematic, you can leave.
Before you travel, I would tell them and your parents that the past history of drinking makes you uncomfortable and that if things begin to get out of control, you will excuse yourself and leave. This way it puts the burden on them to moderate. If they persist in their behavior, you explained the rules ahead of time.
If you leave, have a talk with your children about the importance of family (the reason you continue to visit) but that there are times family members must set limits and boundaries on behavior that is unsafe or inappropriate. Being around people who are drunk is not something you want to expose them to or be around. Altered states change people in ways that are not always nice. This is a hard line to take but one that will earn the respect of your children and may cause others to rethink their enabling behavior. Don’t allow anyone to put guilt on you for setting boundaries. You are not telling your family what to do, but telling them what you will or will not tolerate to keep your family safe.