Divorce suggestion

My brother got married in september last year with a delhi based girl. We were satisfied with her and her family before marriage. But after few months of their married life she said that my father intentionally touched her inappropriately and created issues and on the other hand my father always considered her as her daughter. Fulfilled all her wishes like buying her favourite foods, clothes etc. My brother also took her side but this matter solved and my papa and she started talking in normal manner. She is physically unfit too as she is suffering from severs allergies and kidney stones. We also providing her necessary treatments. She also said that she always suffered from depression before marriage as her family and siblings never treated her nicely and talked a lot against them but we always tried to give that emotional support. 2 months before she visited her parents home and few days back she said that my brother was not behaving good with her. He drinks and have affair too. Without any proofs and my brother is not that kind of boy. He constantly trying to calm her down. Me n my family called her so many times and her family always misbehaved with us. My brother also convinced to live with her conditions but still her list of conditions are never ending. She wants my brother to live without my parents. She wants my brother to end all his relationships with his friends. All and all she and her family is mentally harrasing us. They also hide few things about her before marriage that she is having allergy problems, she is severely depression person, she is suffering from ghost n all problem like kaali mata enters in her body and her family justifies that it is completely normal. She went to baba's too. She undergone eye laser treatment as her eye sights were too weak. We are in a state of serious stress. My father and brother are on a reputed job and this harrasment constantly affects their physical and mental health. Please suggest what to do and how to do. What should be the proofs we required to file a case against them.