Is it permissible to give the expiatory alms for a sick parent's fasting (fidyat siyam) to a poor, sick man who is unable to fast?

If the father is suffering from an illness from which recovery is not expected, he is not obligated to fast. Instead, he must pay an expiation (fidyah) by feeding one indigent person for each day, and it is sufficient for him to pay this expiation to a single indigent person.