How can one act to reconcile between two brothers, one of whom has severed ties with his brother because his daughter eloped with another man and he refused to marry her to his son? And what is the religious ruling concerning a girl being ostracized by her family and relatives after her marriage?

Reconciling disputes is among the best deeds in the sight of Allah. Islamic law has forbidden turning away from each other and estrangement among Muslims, especially among kin, because a severer of kinship ties will not enter Paradise. If the niece repents, it is not permissible to boycott her. If she does not repent, then the boycott depends on what is beneficial. Relatives should be advised to abandon estrangement and to communicate seeking Allah's pleasure, as this deprives them of much good and prevents Allah's forgiveness for their deeds. Forgiveness is better and increases a servant's honor, earning them Allah's pardon and forgiveness. Maintaining kinship ties increases sustenance and extends life.