Is it permissible to ostracize a sister who ran away from home and married a man whom the family did not approve of, knowing that she used to talk to him and go out with him before the marriage?

Maintaining kinship ties is obligatory, and severing them is forbidden, even if the sister is immoral. It is not permissible to abandon her; rather, one must visit her and discuss with her how to abandon the sin. It is permissible to shun an immoral relative if a benefit is achieved thereby. However, if the sister repents, it is not permissible to shun her.