When a Muslim mother loses her right of Hizanat (custody)?

Under Muslim law a mother loses her right of hizanat "By her misconduct", such as an immoral life or neglect of the child, because custody exists for the child's welfare. She also loses it by marrying a man who is not related to the child within the prohibited degrees, so marrying within those degrees does not end it. The father's death does not end it either, and the mother's custody continues. Courts decide custody on the welfare of the minor under section 17 of the Guardians and Wards Act, 1890.