In no way should you have to be in the middle of a bunch of drunks. I suggest telling your husband how you really feel and that you'll feel much better not getting involved. It's his family and he can continue if he chooses (although Al-anon is a very good idea).
One effective way of settling a problem like this is to focus on how YOU FEEL during your next conversation with your husband. No one can criticize you on your feelings and he helps the situation on what it is.