Daughter in law torture inlaws

Respected Lawers I would like to tell you my family problem and need your suggestion. My elder brother got married in 2006.At the time of marriage he had not completed his engineering, Few subjects was backlog, but started working in a pvt. Firm. Marriage had done with mutual acceptance. And after marriage both brother and his wife lived in bangalore for 7yrs, till things were ok. After that due to financial problem they shifted to Ranchi home town and stayed with my parents. After that the daughter in law started saying that we have cheated her and married to non engineer. Also started saying that my brother had taken 6 lakhs rupee at different occasion from her family during the bangalore stay. For which my parents were totaly unaware. Now the present situation is in 2014 my brother got Brain stroke and parallisied, he not even able to speak word. After that my daughter in law started harreshing my parents for money, even though they fullfill all her basic needs, as an when requird give money to her, take care of brother, she lives at my home along with my parents. But she always use slang, always disrespect and at one occasion she hits my mother. Her brother is goon type and always support his sister for every wrong doing and provoke to harm us, sometimes her brother calls and use slangs on phone to my father. Due to terror and social disrespect my brother and parents dont say anything to her, but she always torture and says that she will put everyone in jail by false alligation and Domestic voilence. Our whole family is totally disturbed and helth of my parrents are also detoriating day by day. My father is a BP and Sugar patient. We have given a informetery to civil court 3yrs back mentioning all the situation. We are not able to get off this situation. Please suggest us.