How can a woman deal with her husband's sister who accuses her of witchcraft and spreads rumors about her, taking into account that the husband's sister suffers from a psychological condition, and the wife wishes to cut ties with her but fears that this severance would constitute a severing of kinship ties?

It is advisable to be patient with one's sister-in-law and treat her kindly, and to respond to injustice with forgiveness, hoping for Allah's forgiveness, for forgiveness is one of the virtues commanded by Allah and His Messenger, and the deterioration of mutual relations is among the destructive matters. It is not permissible to abandon a Muslim for more than three days unless there is a legitimate benefit, and if her connection causes troubles, one can suffice with a minimal degree of connection, or abandon her if the connection brings evil.