Legal analysis: whether the younger brother should pay back the money after the elder brother owes it should be determined according to the actual situation. If the younger brother does not guarantee the debt of the younger brother, the younger brother will repay the responsibility free of charge, and the older brother will repay it with his own property; If a younger brother guarantees his brother's debts, and his brother is unable to repay them after he owes money, the younger brother shall bear the responsibility of guarantee and repay the debts to the creditors within the scope of guarantee. The scope of guarantee generally includes the principal creditor's right and its interest, liquidated damages, damages and the expenses for realizing the creditor's right.

Legal basis: Article 675 of the Civil Code of People's Republic of China (PRC) stipulates that the borrower shall repay the loan within the agreed time limit. If the term of the loan is not agreed or clearly agreed, and cannot be determined according to the provisions of Article 510 of this Law, the borrower may return it at any time; The lender may urge the borrower to return it within a reasonable period of time. Article 681 A suretyship contract is a contract in which the surety and the creditor agree that the surety will perform the debt or assume the liability when the debtor fails to perform the due debt or the circumstances agreed by the parties occur. Article 691 The scope of suretyship includes the principal creditor's right and its interest, liquidated damages, damages and expenses for realizing the creditor's right. Unless otherwise agreed by the parties, such agreement shall prevail.