Solution to harrasment by my brother in law and father in law

Hi, i am a govt teacher by profession . My husband died 3 years ago, he purchased 1000sq yards when he was working abroad but on his father's name in the year 1991 . father gifted 655sq yrds of property on my 2 sons and my husband 125 sq yards for 2 sons and 530 for my husband and that gift deed was registered in 1997. After knowing my brother in law bad intentions i did partition deed of 125sq yrds and 530sqyrds between my childrens and myself.Now my brother in law is trying to sell that 655sq yards land i wanted to know if he can do it ? My father in law is alive . and they are harassing me saying that all that property belongs to my husband's father and they will put case on us. They are abusing me verbaly, and my father in law and brother in law live in our house which is registered on my sons name. BIL is married and has 3 kids. I do not want my brother in law to stay anymore in my home as we are facing lot of problems . He is demanding 15 lakhs as his fathers share because in islam there is 1/6 part of property given to father if he is alive . he has brainwashed his father and now father says he has never signed the gift deed.he is 82 years old and has cancer last stage doctors said 6 months time. Is there any solution ? am very confused now. What are the legal options available for me now ?