Can grandson file a case on ancestral property sold 18 years back

Hi, We bought a land in Bangalore 18 years back (1998) from a person (lets call X) who took the GPA of the property. This property was an ancestral property (coming from generations) and GPA was registered to this person X by the father in that family. By this time his son was minor (about 8 years old). Now after 18 years, can the son claim this property back? We've been having a small shop in that place with electricity bill on my name (built in 2006). However during the construction of this shop, the grandson had previously claimed that he will go for court if didn't settle for an amount, so we had paid him some amount but he refused to sign any documents on this and leave it there. Now we want to demolish this shop and construct a house in its place. So can the grandson still claim this property back? We're scared to demolish the house as he will again come back and ask for money/file a lawsuit on us. Please suggest. Additional Info: 1) I don't know if the ancestral property was divided equally amongst the family members and if the father sold only his share of the property. 2) They still have other property in the same area which is still ancestral. but I don't know on whose name is the property on right now. Regards, Kishore.