Is it permissible to inform the father about his daughter who speaks to men under the pretext of friendship?

A woman is not permitted to converse with non-mahram men without need, especially if such conversation takes place in private and leads to temptation (fitna). If your sister engages in this, it is a reprehensible act (munkar), and you must advise her gently and kindly. If she does not stop, threaten to inform your father and boycott her if that proves beneficial. If these means are ineffective, inform your father so he may admonish her; for he is her guardian and responsible for her. Allah the Almighty says: "Allah instructs you concerning your children" (An-Nisa, 11), and "Protect yourselves and your families from a Fire" (At-Tahrim, 6). And the Prophet, peace and blessings be upon him, said: "Indeed, Allah will ask every guardian about that which he was entrusted with."