My brother is currently in prison paying for his mistakes in Perth. His daughter was born here in Victoria in Feb 2016 and both his partner and the baby have been living with my mother. She spent a month in Perth visiting my brother in prison and her family and while there, was using Ice. She is a drug addict and while she does not use while staying with my mother as soon as she leaves to go to Perth, she uses it again and we have no idea what is happening to my niece while she is in Perth. My brother wants her to leave the baby with me and my mother while she goes to Perth but she will not. He is scared of what might be happening or might happen to his daughter while she is using. What can I do to stop her from taking the baby with her under family law?