Can a false case be filed against my brother in this situation?

Hello, My brother had a relationship 4 years back with a girl, it continued for some time but then her family got to know about them. The girl said her family used to torture her a lot, didn't give her to eat and was in a pathetic condition. They did not meet for some time and one day the girl left her house without telling anyone and reached my brother's home one day. The boy's father didn't help her because there could be a case against him and suggested her to go to her home. She went, don't know where and one day message came that she is ok and with her family. After 4 years, she called my brother again and said she wanted to meet him. She told him that she is again being tortured by her family and he has to help her. They were not in touch for four years at all, not even a single call or message. When my brother refused to help her she started blackmailing my brother that she will file a case of harassment and brain washing her mind and call the police. She wanted money and when my brother refused, she said that. My brother said he has not even touched her once because they met only twice. She is messaging him every day and he is not replying to even a single message. What can we do now and what can be the worst case scenario? Can a case be filed against us and are we under threat? Please help