Legal analysis: If there is no guarantee for the loan, the children have no obligation to repay the bank loan owed by the parents. If a guarantee is made, it needs to be repaid. In fact, there is no legal basis for "father's debt and son's debt" or "son's debt to father". Neither "father" nor "son" has such an obligation to repay.

Legal basis: "The People's Republic of China and the Civil Code"

Article 675 The borrower shall repay the loan within the agreed time limit. If there is no agreement on the loan period or the agreement is unclear, and it 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 676 If the borrower fails to repay the loan within the agreed time limit, he shall pay overdue interest in accordance with the agreement or relevant national regulations.