Is it permissible for a person to pay off his father's debt from his zakah?

Question : If the father has a debt and the son is wealthy, and the father is unable to pay off the debt, is it permissible for the son to pay off his father's debt from his zakah?

Answer : Well, some scholars have said that it is not permissible. The correct view is that it is permissible, because paying off a parent's debt is not obligatory for the son. What is obligatory is financial maintenance, whereas paying off the debt is not obligatory. And if it is not obligatory, then if he pays off his father's debt from his zakah, he is not saving himself anything. Is it reasonable that I go and pay off the debts of so-and-so and so-and-so, while my father has a debt and I do not pay it off?
This is not wise. Therefore, we say that it is permissible for a person to spend his zakah on his relatives, including his fathers, mothers, sons, and daughters, in cases where he is not required to pay this zakah as an expense or the like. Whatever the son is not required to pay off, it is permissible for him to pay it off from his zakah on behalf of his father.