Threatening to suicide if divorced

Dear Sir, My Brother(age 22) was in love with a Girl(age 23), they both ran away from home to City and got married as per Muslim act. We have never accepted their marriage. Time passed on, Girl used to visit her parents and my Brother visits our home. Things did not go well between them and after 6 months Girl came back from City to her home town and stayed for 4 months. One day my Brother too came to visit our home, next day Girl saw that and created nu-sense in neighborhood. Brother went back alone to City, Girl complained in PS we have kidnapped our Brother and hide him. Few weeks later Brother came back to PS and witnessed its all false allegations. We got clean chit from PS and same day we wrote an Affidavit of Deed of Disowning. My mother signed and submitted in PS got acknowledged on it From that day my Brother never came to our home again. Girl created more nusense by approaching Mahila Mandal saying that my mother is responsible for all her married life disputes Its been totally 6 months for now they are separately staying. Brother in City and Girl in town with her parents. Now my Brother is planning to divorce but Girl is THREATENING she will COMMIT SUICIDE and will write a letter stating responsible people are my brother and all my family members (Father, Mother, Brothers and Sister). She is also threatening to file false cases which ever is possible (Harassment, Dowry, Domestic Violence etc...) Could you please guide me how can I save my family from getting into legal actions Will we be blamed if she commit any Suicidal attempt Will be any case gets booked on my family and How can my brother proceed for divorce with minimal risk Thanks a lot in Advance for all your guidance