What is the ruling on a sister shunning her brother who stole from her, insulted her husband, and slandered her?

It is not permissible for a Muslim to transgress against his brother's honor or property, or to humiliate him, for the Prophet, peace and blessings be upon him, said: "Indeed, your blood, your properties, and your honor are sacred among you, like the sacredness of this day of yours, in this month of yours." Whoever does so must repent and restore what was wrongfully taken. The wronged person is advised to forgive, seeking reward and preserving kinship ties, for Allah Almighty says: "And those who pardon people; and Allah loves the doers of good" and "So whoever pardons and makes reconciliation - his reward is due from Allah." Nevertheless, he is permitted to reclaim his right or treat the oppressor in kind, but this is not advised.