Is the failure to visit one's father in the hospital the day before his death considered an act of disobedience, knowing that he died pleased with his daughter, and what can be done to atone for this feeling of guilt?

If a son was dutiful to his father throughout his life, his actions are not considered an act of disobedience (ʿUqūq), and Allah will overlook his lapses, for Allah the Almighty says: "Your Lord is most knowing of what is within yourselves. If you should be righteous, then indeed He is ever Forgiving to the often returning [to Him]." And he atones for any shortcomings by consistently supplicating for his father, giving charity, honoring his father's friends, and maintaining ties with his father's relatives. This is a form of dutifulness that does not cease with the father's death.