I'd call this Betty "friend" and tell her something along the lines of "I have heard on 3 separate ocassions from people citing you as a source for gossip about my father's second marriage, and also invoking my mother's memory by saying she would be disappointed in my father. Now, the cherry on top is that I heard from a friend who is a teacher that she overheard 2 of her classmates discussing MY FAMILY and the divorce in a very unflattering way, and I can only assume that once again the source for this gossip was you. So i'm calling to ask you to please stop discussing my family members and spreading falsehoods. You probably aren't even aware that your stories are being spread from person to person, and most hurtfully, are coming back to me and my sister in a most painful and hurtful way. If you respect my mom's values so much, then I ask you consider the hurt and frustration her daughters are going through hearing their family members discussed like guests on an episode of Dr. Phil. No one ever knows every side to every story. So if you want to be friends with Sarah, go ahead. But if you consider yourself a friend of my family as well, then please stop talking about our business with other people."