Is avoiding a verbally abusive grandmother considered a sin, knowing that normal interaction with her leads to harm?

The grandmother is among the foremost of kin in terms of maintaining ties. Many scholars have gone as far as to say that being dutiful to her is obligatory, like one's mother. Mistreatment by her does not permit mistreating her in return or cutting ties with her, except to the extent that removes the harm. Therefore, you must maintain ties with her, treat her kindly, and be patient with her.