What is the religious ruling on a wife remaining in her brother's or sister's house without her husband's approval? Is this considered nushuz (disobedience/rebellion)?

A wife must obey her husband regarding residing with her mother, unless harm results from it. If she disobeys him in this without a valid excuse, she is considered disobedient (nashiz). As for her staying in her sister's house while her sister's husband is present, it is permissible if the Islamic guidelines are observed. Both spouses should strive for understanding, overlook minor mistakes, and consider each other's circumstances.