[Stang_Crazy]

As much as it sucks, you kind of have to let your sister make her own choices and decisions. Did your father treat her bad and yell at her? Yes. But it's still up to your sister if she wants to continue a relationship with him....regardless of how counter-productive it is.

It sounds like you're in quite a situation...I wish you and your sister all the best and I hope everything works out.