It's immoral to cannibalize another person.
Henry is lost and hungry in the middle of nowhere and his friend who was with him just died.
Henry wants to eat something.
Henry buries his friend and begins to collect edible plants, so he can eat.
Henry decides that the only way that he can survive is to consume the meat of his friend.
Henry is able to get enough nutrients to survive long enough until he is rescued.
Henry is rescued as he is eating and is forever shunned.