Re. Gift Deed

Thank you for posting a reply to my query. The donor was under not misinterpreted or influenced, the gift deed was executed out of pure love and affection in 2005, he was present at the registrar's office signed in front of him. Over a period of time the relationship is not the same and also the escalating real estate prices may be a cause for cancelling the gift deed. He is demanding me to pay a certain amount or threatening to go to court. Does he have a case. Please advice?