Legal analysis: the money owed by the father belongs to his personal debt, and the son has no obligation to repay it. In the second case, when the father dies, inheritance occurs. According to Article 33 of the Inheritance Law: "Inheritance shall pay off the taxes and debts payable by the decedent according to law, and the payment of taxes and debts shall be limited to the actual value of his estate.

Legal basis: Civil Code of People's Republic of China (PRC).

Article 509 The parties shall fully perform their obligations as agreed. The parties shall abide by the principle of good faith and fulfill the obligations of notification, assistance and confidentiality according to the nature, purpose and trading habits of the contract.

Article 563 If a party fails to perform its obligations due to delay in performance or other breach of contract, it may terminate the contract.