<human>: So, my gf has come to the conclusion that if her "friend" isn't a full blown narcissist, her friend is at least incredibly selfish and makes life difficult when she doesn't get her way. I don't get how female friendships work. Anyway, the only advice i was comfortable with giving her was to follow the golden rule. My gf wanted to just ignore her and hopefully she would just get the hint but if I were the "friend", I would at least want a chance to be heard. 

As a note, a lot of the tension manifested when I started dating my gf because I take most of her time now and this causes some issues with the friend. Also, this "friend" is imho just not a very good person. She really is the type that will take from you as long as you let yourself be available until you're used up. Also, she uses awful threats to get her children to obey her. 

They are going to have coffee tomorrow night. My gf thinks it will be pointless, get nasty, and will almost certainly be turned. What advice could I give my gf to make this a productive meeting?

Summarize the given text in a few sentences.
<bot>: Gf doesn't want a relationship with her best friend anymore. I don't think my gf should just drop her like a sack of bricks and give her a chance to reconcile their friendship if possible.