Mr. X sold vacant sites through GPA in favour of Mr. Y registered in the Sub Registrar Office, Bangalore in the year 1980. Along with GPA, Mr. X gave a Affidavit which says, at any circumstances this GPA will not be revoked since the full consideration amount received by Mr. X. Now Mr. Y is willing to sell the sites. Mr. X is not alive now. Can Mr. Y execute a sale deed in favour of any person?