
Visible crew/equipment: When Henry helps pull Mark onto the treehouse at the beginning of the film, if you look very closely to the left you can just make out a crew member dressed in black helping him on to the platform. The crew member then ducks back under the platform.
Answer: Henry apparently has what is called a "conduct disorder" - the term used for kids below the age of 18 engaging in what would be (and most likely will become) a diagnosis of sociopathy/psychopathy (antisocial personality disorder) when he becomes an adult. He is "evil", highly manipulative, self-centered, without remorse or other true feelings, and probably incapable of forming loving or long-term attachments. Many sociopaths are believed to have above average intelligence and make good imposters, capable of fooling others because they come across as "charming."
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