I think that's exactly what she should do.....because if she's considering leaving anyway, why not try to put an effort into it first. If it don't work out and the supervisor ends up picking on her, then she could leave like she was originally considering anyway.

I'd encourage her to fight back because in order for the problem to be fixed, or even noticed by the other bosses somebody has to step up.

She was there first.

Good Luck, I hope it works out for your friend.
Desirae