Property dispute in the Family

We came to know that my Uncle (Mother’s Brother) has transferred all the Property of my Grand Parents (both Grand Father & Grand Mother) without taking any consent from mother (My mother is 1st child of my Grand Parents and my uncle is the 2nd). My Uncle has passed away couple of months back and after his death we came to know that my Uncle has transferred all the property by providing false Vamshavriksha where he has shown that he is the only child of my Grand Parents. Now my uncles family are trying to transfer the property in their name. I need to know how my mother can claim her Share.