Legal analysis: from a legal point of view, sons have no legal obligation to repay debts instead of their fathers; However, under the following circumstances, the son should repay the debt instead of the father: 1. Accepting the father's gift makes the father's debt unable to be repaid, regardless of whether the gift is conscious or unconscious; 2. Inherit the inheritance from the father and undertake to accept the debts within the scope of the inheritance; The debts borrowed by the father are used for family life, especially the life of the son who lives with his father.

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

Article 161 The successor shall pay off the taxes and debts that the decedent should pay according to law within the limit of the actual value of the inheritance. The part exceeding the actual value of the estate shall be voluntarily repaid by the heir.

If the heir renounces inheritance, he may not be liable for paying off the taxes and debts that the decedent should pay according to law.

Article 162 The execution of a legacy shall not prevent the legator from paying off taxes and debts according to law.