How to identify if papers of property is real

Sir. My father has 2 brother. All the property was self-earned by my grandfather. My grandfather made a testament in favour of the second brother of my father. But due to some problem, my grandfather cancelled it. In last month my grand father died. My father second brother taking all property with the help of testament made by my grand father. How I can find its true or not. We dont have any document related to cancle of testament.