law for minors

I wanted to know what legal action we can take about my niece who is 17 years old. She ran away from home. This is not the first time she did it. She even eloped with his boyfriend and claims that she is residing with a friend now. When in fact the aunt of her boyfriend said that she wont leave their house because she ran out of money. Her mother openly said that she can come back home since she wasn't even told to move out in the first place. We spoke to her cousins and they said she was asking money from them for she hasn't been eating for a few days. We'll actually she did not just ran away, her relationship with her mother was perfectly fine until one Monday, she went to school and never came home. Since her sister is her schoolmate, we found out that she is still going to school. Then we later found out that an uncle of her asked her to have his cell phone sold for 2500 before this happened, she sold it for a lower amount then ran off with the money. She ma secretly makes contact with our mother which is her grandmother who is already 72 years old and asks help so she can get by. I am really concerned about my mother actually and would like to know if there is something we could do for them to stop asking money from my mother. It's like she is the only person they can fool.She sends words not fit for a girl her age on their school chat room saying nasty things about her sister. There was even one time her mother asked her to come back home but she refused to come back. She will be turning 18 this November, is there any legal action we can do so we can prevent her from damaging the life of our mother and others as well? Thanks.

seek DSWD's help.