I feel bad for her. I have two females: Maddie was two when we brought home Cooper at around 14 weeks old. Maddie hated Cooper. I have worked really hard encouraging their relationship.
After about 4-5 months, they became sociable.
I had to take them to the groomer together and drop them off. When I came back they were totally different dogs. (I joked that they were praying at the groomer: "Please God just send mommy back and we'll be good, we promise.")
From that day on, they were buddies. I think it is a female thing, but they still have thier tiffs. However, they also lick eachother's faces
and play together constantly.
I hope it works out for your friend. I know the grief I went through stressing about this. I just wanted them both to be happy.
~Amanda