This involves tedious process.
You cannot monitor the process sitting outside the country outside the town/place where the proerty situate.
First identify the village where the property situate, approach the Village administrative officer/village munsif, verify the details of the land owners from the olden days patiently because there may be exhaustive records hence patience is required to go through the records to find out if your grandfather's name is found against any landed property.
If you get any clue , you may catch the link and progress to penetrate looking for the details.
After that get an encumbrance certificate through registrar's office, find out on whose name the property currently stands and what all transactions took lace in between through what all documents, get the certified copies of those documents which would establish the title and the link for title in the past.
After ascertaining the facts, you may proceed legally to retrieve your property, if there is any.