I suspect that when your friend asked you to advise her niece,she was hoping what you said would somehow mean that the couple would make everything up and decide not to divorce, instead the divorce is going ahead, she is upset and doesn't want to talk about it.
People also get angry because they feel defensive about things, that she perhaps suggested to someone that your involvement might help and it didn't and they feel defensive about that.
You say that she has acted this way before, so it was hardly unexpected. For all of us, we tend to like our friends, despite their funny little ways, we just have to decide how deep the friendship lies.
I had a friend(sadly, now dead) who came from one of those families where sisters had rows and didn't speak to each other for 20 years - and she could be very explosive and verbally abusive, despite this, and she rarely had rows with me, because I wouldn't respond, but despite her trigger temper, I fundamentally liked her and enjoyed her company, and after one episode, I did distance myself for 6 months, but we got together again.
What you now need to decide is whether you like the persosn behind her trigger temper, in which case you factor it in and deal with it, or whether her trigger temper, is enough to destroy the friendship.