How to register property legally in India

Dear Sir, My father owns a property in rohini delhi (26 yards plot)in which he is residing for the last 20 years.IN year 2009, he , in lieu of some loan, transferred the property in the Lender's name. And by the time , we repaid the loan, i.e. in 2011-12, the GPA was not allowed and for registry my father was not having enough funds. So we only taken the papers back but GPA was not registered in my father's name. And still the Lenders name is entered in the revenue records of government as SELL, AGREEMENT TO SELL THROUGH GPA IN 2009. Kindly advise us what to do. My father is very old person and kindly suggest us what to do so as to avoid any future issues for my younger brother.