What to do

I need suggestions, so PLEASE help me. My sister and her son moved down here at the beginning of April and it was our understanding that because my birth mother and her ex(Jim) were split up and fighting that Jim was going to rent an apartment down here for Melody because it was the best place for her. Now fast forward to today. I talk to Melody only to find out that this past weekend when she was visiting with Susan and Jim, that they kept trying to get her to move back to who knows where. Jim also told Melody that as long as she is here he won't send her any money. Melody is bringing in some money here and is helping with bills. She is also looking for a job, but at the time she doesn't have enough money to get an apartment alone. Should I just tell her that she should go back to living with her abusive mother, or do I let her stay here until she finds a room-mate. I really enjoy her being here, and especially since she has money, I am not supporting her 100%. If anyone knows of anyone looking for a room-mate, please let me know ASAP!! Thanks