Some people just hold onto grudges longer than others. Some things are unforgivable, I understand that, but when it is something that an apology should make things better and it doesn’t; well, I have decided being friends with people who hold onto grudges like that are not people I want to be friends with. The people I know like that tend to be insecure, and I think they get some sort of satisfaction feeling better than the other person. That making the other person feel horrible for an extended period of time is some sort of power thing. I am the opposite even sometimes when I am still hurt by what someone did, if they apologize and want to clear the air I do my best to release them from their torment of feeling badly for what they did. I want friends like that. I think when everyone trusts each other, trusts there is never mal intent, even though sometimes we do thingsvthat hurt others, then things can be forgiven.
I don’t know the exact situation your friend is having, but if it is similar to some things I have been through, I initially was very upset, it was a loss and I went through a grieving process. Eventually I got to the anger stage, fuck them for lording over me a mistake I made when I never meant to hurt anyone and I really feel badly about what transpired. I don’t mind giving someone some time of they were hurt badly, but it can only drag on so long and then they have become the mean ones. After I get through the anger and become apathetic, that’s when miraculously the person usually wants back into my life. If I let them in they will never be someone I really feel close to again. I can’t be very close to someone who can hate me like that for a prolonged time.
Hopefully your friend will move through the stages quickly and she will move on to make new friends fast.
If she were my friend I would tell her how awful I think those people are and share a story of my own to show empathy. That is if I understand the situations correctly and am not projecting too much.