Is a mother entitled to control all aspects of her daughter's life, including her friends and fiancé? And is it permissible for her to forbid private conversations with the fiancé and demand that her daughter disclose the details of their discussions, especially given that the daughter is over 21 years old and feels her privacy is being violated?

The rights of parents are great, and showing them piety is obligatory, especially the mother, and disobeying her is one of the gravest sins. Obedience to them is obligatory in what is good, in what benefits them and causes no harm to the child. If the mother asks about her daughter's friends out of fear for her from bad company, this is a legitimate and commendable intervention. As for the suitor, if he is not yet contracted, he is a stranger, and it is not permissible for him to be alone with the fiancée or to converse with her without need. Nor is it permissible for her mother to be alone with him or to converse with him. If the legal marriage contract has been concluded, then he is her husband; it is permissible for him to converse with her and to be alone with her. However, if the mother instructs caution regarding being alone with him before the consummation, then obedience to her is obligatory.