Is it permissible to take from the mother's Zakat to pay off debts, what is the ruling on deducting Zakat from a debt, and who is more entitled to financially support a son who is unable to earn a living?

A father must spend on his poor son who is unable to earn a living. If the father is unable, the obligation transfers to the wealthy mother who is capable of spending. It is not permissible for the mother to give her Zakat to her son to pay off his debt and count that as a debt owed by him to her. However, it is permissible for the mother to give her Zakat to her indebted son to pay off his legitimate debts, because those in debt (al-gharimun) are among the categories eligible for Zakat.