We are followers of the Maaliki Math-hab.

Answer

According to the Maaliki Math-hab, the obligation of Sadqah Fitr is compulsory on the head of the family. He is liable for the Sadqah Fitr of all those of the family who are reliant on his support. Thus, a man has to pay the Sadqah Fitr for his wife, children, parents (if they are poor).

Adult children who are by the means to pay their own Sadqah Fitr are not the responsibility of their father. They have to pay their own Sadqah Fitr.

If one brother pays the Sadqah Fitr of his other brothers who can afford to pay, then this too will be permissible on condition that they are made aware of the payment prior to discharging it.