Is a person considered sinful if he resorted to deception to obtain additional money from his father to cover study expenses, and could his failure to find a job after graduation be due to this act, and what should he do if he is sinful?

The basic principle is that deception to acquire money is forbidden, and it is even more forbidden when it is from a son to his father, as it combines the sin of aggression with that of filial disobedience. Insufficient financial support does not permit this, for the father is not obligated to spend on his adult son according to the majority of scholars. One must repent to Allah and absolve oneself of this obligation towards the father by returning the money or seeking his forgiveness and pardon. It is sufficient to deliver the money to him by any means, or to seek pardon without informing him personally.