What is the ruling on severing ties of kinship with relatives who mistreat the mother and father of the one who severs the ties?

Maintaining kinship ties (Silat ar-Rahim) is obligatory, and severing them is forbidden. Harm from relatives is more painful. Their harm must be met with patience. Their harm does not negate the obligation to maintain ties with them; rather, it negates harmful forms of connection, such as visiting, while other forms remain, such as greetings of peace (salam), assistance, and prayer (du'a). Kinship ties are fulfilled by everything considered a connection by custom ('urf), such as delivering good and warding off evil. Responding to ill-treatment with kindness is one of the best ways to bring about reconciliation.