Shailja Singh rathore 28 July 2020
G.L.N. Prasad (Retired employee.) 28 July 2020
First get such information from nearest relatives/friends of your grandfather, and then make an approach to local advocate and take his guidance for publishing such Notice that your father is the legal heir and your father is having all rights on deceased grandfather's properties, dealing without his intervention is not legal and binding on your father. Also contemplate in issuing notice to your Paternal aunt for disclosure of those assets owned by GF.
P. Venu (Advocate) 28 July 2020
Your father can take a search of the local Registrar's Office. The information in the revenue records could be obtained under RTI.