Is expiation (kaffarah) obligatory for one who broke his oath (hanath fi yameenihi) while being able to feed others, but he thought it was not obligatory for him due to his young age and having no family?

The expiation for an oath is obligatory in sequence. Fasting is not sufficient unless one is unable to feed, clothe, or free a slave, as stated in the Holy Quran. If a person was an adult at the time of taking the oath, then their oath is binding, and expiation becomes obligatory upon breaking it, even if they have no dependents. If one expiates by fasting while being able to feed, clothe, or free a slave, then that expiation is not sufficient, and they must expiate through one of these options. However, if the oaths were taken before puberty, they are not binding, and expiation is not obligatory upon breaking them, because the pen is lifted from a child until they reach puberty.