I have a half-sister, and her mother has remarried. Her uncle does not agree to give her to us amicably, claiming that he raised her for 11 years and does not leave her with our stepmother, who is my mother. My father is abroad and does not agree to bring her to us because custody has been lost from her mother. My sister's uncle has young men who are not her mahrams, and due to the nature of his work, he is absent for days and weeks. I want to protect my sister so that she does not live with young men who are not her mahrams. What is the legal way to do this? I need your help in finding a solution.