What is the son's responsibility towards his deceased infidel father, and is he obliged to wash him, shroud him, pray over him, and bury him?

It is permissible for a Muslim to bury a disbelieving relative, and this does not contradict his hatred for their disbelief. Burying a disbelieving father is a form of good companionship in this world. However, after burial, it is not permissible to supplicate for him or seek forgiveness for him. It is not prescribed to wash a disbeliever, shroud them, or pray over them, and the Prophet did not command this. Similarly, it is not prescribed for the relatives of a disbeliever to follow their funeral procession.