Is feeding a needy person sufficient for making up for last Ramadan's fasting?

If a father breaks his fast in Ramadan due to an illness from which recovery is hoped, he must make up the days he missed. If he deliberately delays making up these days without a valid excuse until the next Ramadan arrives, he must feed a poor person for each day he delayed the make-up. This feeding is not sufficient if it is done before it becomes obligatory and firmly established as a debt, unless he was unaware of the prohibition against delaying the make-up, in which case the feeding is not obligatory for him.