May weak women and children leave Muzdalifah after midnight and proceed to Mina?

Yes, it is permissible for weak women and children, as well as persons with disabilities, to leave Muzdalifah for Mina after midnight. Healthy guardians may also accompany them to assist the weak and the sick. Without such an excuse, it is not proper for anyone to leave for Mina without performing Fajr at Muzdalifah. If one does leave, one must offer a damm.