Inheritance from father

Hi I'm a Muslim wife born to hindu parents. My father passed away recently. He and my mother were staying separately for 14 years. My mother was threatened to not return home one day after work when I was young. She left without her belongings and certificates. She filed a complaint after some time that they had her belongings and jewellery But they asked her to bring bills. Her father had died. With no support she decided she will take back the case or she would have to run to courts and the police to get her children back and lose her job if she kept up fighting. The case was taken back and we shifted to a rented apartment. My father stayed with us a little while and then left us to stay in his paternal house. He didn't contact us after that for11 years until 3 years ago. He died recently. Three years ago he told us that the property was undivided. He died recently but not his brother or sisters are not letting us know if he left us something. How do I know about his bank accounts, policies and locker? He was not mentally sound in the last 1.5 years says his brother. How do we know if he has been deceived into signing property papers? Can I contest it and fight for my right?