Dear Arie1276

You chose to accept the invite to go around even though you know that the situation between you & other family members/inlaws is volatile. You were sober and capable of walking away the moment things began to get uncomfortable especially since you saw that they we really drunk by the time you arrived.  You in your post you say that you & your son used the F word on several occasions during this visit. So its a bit like the pot calling the kettle black.  I think you are right to keep any future meetings to a minimum & act with dignity and walk away from anything that you find provocative. It is up to your nieces parents to go into bat on her behalf.