"If he doesn’t see the problem, and it’s hurting others, then it’s time for you to question his motives too."

I thought that, too. It's hard to say. It could be the girlfriend has lots of other good qualities and the nephew is overlooking the negative or even letting her know how it bothers him and others with a warning. Certainly if the nephew knew of the rudeness towards the aunt that would be grounds for at least an apology to the aunt, let alone a break up. If not then the aunt knows that there is very bad blood in the family that they were not aware of and should adjust their interactions, if any.

You need some butter biscuits to go with the coffee. How good it would be on the shore of Long Island having a coffee break and butter biscuits! Then a long walk on the beach. I would love to be there right now!