Query on Sale Deed Registration

Dear Experts Around 10 years back, One man has borrowed money from my father for his personal use. While giving him money my father has done some paper work on 100 Rs Stamp, stating that If I am unable to return your money you will have rights on my 1 Bigha agri land. Now almost 10 years has passed Neither he is giving us land nor money. During my last interaction with him he gave me deadline of 10 April 2015 that if he is unable to paypay money then he will execute sale deed in our favour. Now I am worried because He hold land in co ownership with his younger brother. And his. Younger brother will neither give consent for sale nor he will come to registrar office during sale deed execution. Kindly guide me how can I get out of this Problem. Thanku