Is it obligatory for children to pay Zakat from their own money if their father delays paying it on their behalf, knowing that he is doing so as a donation?

Zakat (definition) is valid if the father pays it on behalf of his children with their authorization and permission, because Zakat is an act of worship that requires intention; otherwise, it is not sufficient. Furthermore, Zakat is obligatory immediately and must not be delayed except for a slight excuse, such as searching for an eligible recipient among relatives or those in greater need.