Is it permissible for the father of the one who broke an oath to make expiation for his son's oath by feeding ten needy persons, or is it obligatory for the one who broke the oath himself to give it?

It is permissible for a father whose son is obligated to pay an expiation for an oath (kaffarat yamin), or for anyone else, to pay that expiation on his behalf from his own private wealth, provided that the person obligated to pay the expiation grants him permission. It is not a condition that the expiation be paid from the wealth of the person who took the oath. If he does not grant permission, it is not valid, because fulfilling an obligation on behalf of a living person is not permissible without their permission, due to their need for the intention. As for a deceased person, permission is not required.