An adult young man abandons the fasting of Ramadan deliberately. Should his father offer Zakah Al-Fitr on his behalf?

All perfect praise be to Allah, the Lord of the worlds. I testify that none is worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

Abandoning fasting is a grave sin. Sheikh Al-Islam Ibn Taymiyyah said, “If one does not fast in Ramadan deliberately with no excuse, this is from the major sins.”

Al-Hafith Ath-Thahabi said:

It is established with the believers that if one abandons the fasting of Ramadan without excuse, illness, or purpose, he is more evil than the adulterer, the one who wrongfully takes extra taxes, and the alcoholic. Rather, they doubt his Islam and think that he might be heretic or dissolute. 

It is obligatory on one who abandons fasting to repent to Allah Almighty sincerely along with making up for the days that he abandoned. Concerning Zakah Al-Fitr, it is a separate obligation that the Prophet, sallallaahu ‘alayhi wa sallam, imposed on the young, the old, the free, the slave, the male, and the female from the Muslims, as narrated by Al-Bukhari and Muslim on the authority of Ibn ‘Umar and his father.

If one does not fast in Ramadan, he is not exempted from Zakah Al-Fitr because he is included in the Muslims although he has committed one of the gravest major sins. Zakah Al-Fitr is due from his money if he has money; otherwise, it is obligatory on the one who must spend on him.

If the young man is adult and capable of earning an income, the father does not have to spend on him and does not have to pay Zakah Al-Fitr for him. However, if he is not capable of earning, then spending is obligatory on the father, and Zakah Al-Fitr also.

Allah knows best.