Is it permissible for a father to use his Zakat to pay for his son’s rent, or the fees for obtaining a marriage license, or car installments?

A father is not permitted to give his Zakat to his poor or indigent son, as supporting him is obligatory upon the father. Nor is he permitted to give it to his wealthy son. However, it is permissible for him to give it to his indebted, insolvent son if the son is unable to repay his debt (categorized as al-ghārimūn – those in debt).

If the son's rent is a debt upon him and he is unable to pay it: 1. If his support is not obligatory upon his father: The father may give him Zakat to pay off the debt. 2. If his support is obligatory upon his father and the father is unable to provide him with housing: The father is not permitted to give Zakat to pay the rent, nor to buy a car for the son.