Is it permissible for a girl to live alone in a separate house from her parents without marriage or divorce? And does the brother's intervention in this matter constitute disobedience to the parents, especially with the mother's approval and the father's personal request for him to intervene?

An adult, trustworthy woman living alone is a matter of scholarly disagreement, with the preponderant view being that it is permissible if there is a need for it, provided that temptation is avoided and her living alone does not lead to corruption. However, if she is not an adult, or if there is fear for her safety, then it is not permissible. The opinions of the jurists on this matter have been mentioned. The sister has no justification for living alone, and it is advisable to intervene gently to dissuade her.