What must a supplicant do after his father invoked a curse upon him before his death, and how can he show filial piety to his father after his death?

Allah Almighty has commanded kindness to parents and made disobedience to them one of the greatest sins. If a person commits an act contrary to kindness, he must return to being kind to them and pleasing them if they are alive. If they are deceased, he must repent, pray for them, fulfill their will, maintain ties with their relatives, and be good to their friends. He must also frequently repent and consistently perform acts of obedience.