Mental harrassment by mother and father in law

My mother and father in law have two son and both have their single child family, younger one married first and his wife took a villa from my in laws before my marriage. In are living with their elder son in 2 bhk flat.In laws give younger son a villa, he loves with his family on one floor and second floor he put on rent. My mother in law wants me to get out from flat with my son because she only wants to show her relatives that the villa living daughter in law is better then me. Problem is my father in law have cancer. Problem with mother in law is she always misguide her husband that i always disrespect her which is not true. She is just trying to make her point right because villa living daughter in law is a conductor and she is choosen by my mother in law. And elder son wife is choosen by him (me) and I am living with in laws. I didn't tell them anything but because of their unnecessary fights for good environment of my son I moved with my 1 yr old son to my father in law's family home(Punjab Morinda) but it is not devided properly in 5 sons and father in law didn't occupy his area properly his brother is using his most of the area. But now I want to put my son on school that's why I need to live with in laws. But in laws harrassing me that they will put my name on death letter. If I never move from this home they will go to the old age home. Father in law told me when I came to this home 4 years ago then because of me have cancer they are putting blames on me for their every bad situation. My husband and I tried to help them to cure this disease whatever we can do for them. This flat is in my husband name. But in laws harrass me and my family and don't want me to live on flat what I do?