It sounds like this person has problems and maybe their problems have nothing to do with you. I don't know. Maybe you should stay away for them awhile and see what happens. Maybe you should let them go. I can't tell you what to do. But if the abuse continues it may be time to let them go. You don't need someone in your life who treats you like that.

As far as grudges go, I think it's better to forgive. I saw something on Facebook: "holding a grudge is like letting someone live rent free in your head". Grudges only hurt you - the other person doesn't care. Forgive but don't forget - that's my motto.