To make a long story short: We sent out our wedding invites last week, one of those invites went to FMIL "best" friend of 26 years lets call her N (and her family).. FI has known them all his life/friends of the family type thing.
SO here's where the problem comes in: FI gets a call last night that his mom and N got in a huge, possibly friendship ending fight. MIL wants her uninvited from the wedding. FI let me know what's going on, but assured me it's his family he will deal with it. He's hoping that either A. they make up or B. when his mom cools down they can have a chat about what an akward position this puts him in and how rude it would be for us to uninvite them. Sigh. I hate drama, I'm just hoping this all works out.