Seller challenge sale deed of land

When did your father give the money for interest then how did the sale execute by that person?

You have posted contradictory statement, inter alia, that, 

"As surity, he registered his land to my father. We have sale deed and passbook with my father's name....."

Be clear as to whether the borrower has "mortgaged as surity" or "sold by sale deed and passbook" of the agriculture land to your father ?

Is your father in possession/occupation of the land?

Hi Dr. Vashista, It is "sold by sale deed and passbook".  To explain more, the borrower wanted money for his business. He is a friend of my father's friend. Since mortgage agreements are hard to resolve in the future and take a lot of time in court, my father asked, if he can make a sale deed and completely transfer ownership, on an oral agreement that we will return him back the land, if he repay the loan amount with interest. Our intention was, we will sell the land, if he doesn't pay within a year. Now, It has been 18 months, so we wanted to sell, so went to survey the land. Now, the borrower's mother is not allowing us to sell, she warns that she will suicide if we sell the land. They have a lot of other land also. This is just a part of land that they registered to my father for the money. Hope this explains the situation. The borrower has nothing to say now, he is silent, just his mother is creating a scene there.