Threat by sister in laws

Hello Sir, I live in Singapore, I am married, 35 yr old female. I have two brothers and 1 sister and a mother. We are the owner of some property at Katni district (M.P). My both brothers are married but unfortunately not working and my sister is very sick nowadays. I send some money for their livelihood every month from last 10 years. Both of my sister in laws want to ruin our property and not taking care of my mother and sick sister...I used to go to look after them in every 3 months...they don't like my presence there..they want my sister and mother to die and always stop my brothers to look after them in order to get whole property in their name and continuously threatening to my mother that they will apply 498 to my mom and family and they indulge me in false case for domestic violence. They blackmailed my mom and took the signature on the stamp paper for the property. They indulge me in false FIR and took signature on legal undertaking..and now they are threatening me and my mom not to enter in the house. In this case how I can secure myself and my sick sister and mother.