In ch.12,Why does the man help out Henry? Why can't Henry help himself?

Henry cannot help himself because he basically has a concussion from an incident a few pages earlier when he is struck on the top of his head witn a rifle butt. It is never made clear why the "cheerful" man helps Henry, but he does say that a boy that he "thought the world of" was killed today. It could be that Henry reminds him of this boy. Jack was the boy's name. He also mentions that his brother had whiskers like that, referencing Henry, so it could be that he is also reminded of his brother.