Partition of parental property

My Grand father (central govt postal employee) died in May 2014. & My Grand Mother (housewife) in June 2012. Heirs : - 1) My two uncles 2) My Aunt 3) My Father My grandfather died without leaving any will. He had 4 self acquired properties, 1 in his own name and rest 3 in the name of my grandmother. On one property my younger uncle used to live with his family and my grandparents (when they were alive) but now after their death he is not ready either to give us any share in the property or to share the rent which he is getting from this property. The other property has completely been given on rent and he is the one who is collecting rent from there as well. On the third property my elder uncle is staying with his wife and he is collecting all the rents from this one. Last property is of the minimum worth and is an unregistered property bought in the name of my grandmother. My aunt is also staying with her son and his family(his wife and a son) in the ground floor of the first property where my younger uncle is living. Now she is also asking for equal share in the property. She got married in 1970. Will she get an equal share as my father and uncles? If not, how much share she can claim? After her death, her son also can claim on these properties? Both my uncles are living in my grandfather's self acquired properties and are also collecting rents from these properties without any legal rights. Upon asking for our rights they are not ready for any partition and are threatening to kill us. What can we do now?