What are my legal obligations if I know about abuse?

I met a girl online who told me she is being financially and mentally abused by her brother, who lives in Japan. She gives him all her money, and he still demands more. She doesn't want to take any action because she loves him and her mother. I tried to help and advise her, but she refused. I want to know if I am legally safe or not. Do I have any legal obligation or risk to report the abuse or intervene? What are the potential legal consequences if I do or don’t do anything? Please advise on the laws and regulations that apply to me in this situation.