4.2. That apart, the 1st defendant's wife, Mrs. Amma Kannu had given an undertaking that in case of default in payment of loan, in discharge of the debt borrowed for the purpose of the joint family, they together agreed to execute a sale deed with respect to the 1st defendant's property situated in Survey No. 173/5 part at Kalayarkoil in favour of the plaintiff. Only on such assurance, the plaintiff had come forward to extend a loan of Rs. 7,00,000/- (Rupees Seven Lakhs only) to the 1st defendant and his wife, Mrs. Amma Kannu on execution of a promissory note. It has been specifically agreed in the said promissory note that either the said Mrs. Amma Kannu or anyone claiming through her would be entitled to repay the loan amount to the plaintiff. While so, during 2015, Mrs. Amma Kannu passed away. Since the said loan was availed by Mrs. Amma Kannu for the common family expenditure, after her demise, the plaintiff sought for repayment of the aforesaid loan from the defendants several times, but