Family Property query

My grandfather died in the year 2011, and left with 5 sons and 4 daughters. He also left with properties with his name and my grandmother’s name. Before he died, he did not prepare any will and grandmother still alive. After 3 years, my father expired (eldest son) and my mother is still alive. Now, the remaining 4 sons of my grandfather are separating, so they are asking my mother’s signature. Our family (my father, mother and two of my youngest brother and me) came out our grandfather family 20 year’s back. We have not separated from our grandfather family; however my father did an exchange deed, gave some property in his name in exchange of a house in the name of my grandfather to live. We are hearing that 4 of my uncles (my father’s brothers) they did a will with my Grandmother. Can I know how much property we (my mother or grandson) can claim the property. Can we get the full 1 share of the value of the property that is under my grandfather’s name? Can we also (either my mother or grandson) claim our grandmother’s property?