Is it permissible for a father to obligate his son to pay for his educational expenses, which are Islamically incumbent upon the father, especially if the father is well-off?

If a father's expenditure on his son is obligatory, he has no right to boast of it, for he is only fulfilling what Allah has made incumbent upon him. However, if the expenditure is a voluntary act of charity and benevolence, its doer will be rewarded if he intends thereby the countenance of Allah and the Hereafter, provided he does not boast of it. This is because boasting nullifies the reward of charity and is an act of disobedience; it has been explicitly stated that it is among the major sins. Boasting is permissible if benevolence is met with ill-treatment.