How will be property distributed after mothers death

I have an property which is in the name of my mother, sister, younger brother and myself. My mother passed away in 2014. My brother has occupied the entire property. My sister is not will to have any share over the property. Now my brothers lawyer has drafted a case for partition - which will later be settled mutually in the court. In the draft it is mentioned that Parties to suit are governed by Hindu Dayabhag school of law. I have also come to know that my brother has forced my mother to register a portion of the un-divided property in his name. Kindly let me know if 1) the Hindu Dayabhag school of law the correct school of law to br governed in this case. 2) What course of action can i take regarding registration of property by my mother.