What should we do now?

My brother got his liver transplant 8 yrs back..he got married 3.5 yrs back through jeevansathi.com..where he had mentioned about his medical history..and we have proof of it.He is running a medical shop.He had a w yr old daughter.now my sis in law..alwys fight with my brother..my parents..her parents too interfare a lot...some times she threatens she is writing a diary..some times she says she is undergoing deepression..and needs treatment..sometimes she says she wants divorce and what all would be given to her.She and her family laughs and mentally harress my brother over his medical history.Now whenever she wishes she leaves our house and says..I wl come only when your parents will come here along with you to discuss the matter...there she and her family members fights..make fun..threatens my family.She doesnot want to live seprately rather wants to stay with my parents..It has been 3.5 yrs ..nd dere is no hope of any improvment...Can she file any fake case on any grounds..den what should my family do..to protect themselves...my father is a govt employee.....does any case affect his job too??? Plz help.