Must children sever ties of kinship with their maternal aunts who have harmed their mother and falsely and slanderously accused her, especially after one of their sons murdered his father, along with threatening the mother with death, and the mother insisting on boycotting them, and threatening her children with her wrath if they do not do so?

Obedience to the mother in severing ties with the maternal aunts due to their injustice is not obligatory. Obedience to the mother is obligatory in what is good and right, and severing kinship ties is not among that. Strive to maintain ties with your maternal aunts without your mother's knowledge. If you fear her anger, then limit yourself to the minimum degree of maintaining ties. Be keen on advising them, enjoining them to do good, forbidding them from evil, and try to reconcile them with your mother.