The true message of the film... (spoilers)
From the very first scene we see Frank rob his own house. Clearly this is a precursor to the strange antics of the main character. Frank mainly spends his days alone attempting to relive his past life. He has lost touch with the future as we see when he is annoyed by the refurbished library & his belief that Harry's Diner still exists. These are standard traits of a person with dementia- his denial of such a problem is another major trait. For a brief time when the robot is introduced into his life, he recovers some social skills & builds a relationship with the robot after initially disregarding it.
Unfortunately, in the building of this relationship, he uncovers a flaw in the robot's artificial intelligence which helps him exploit the robot to suit his delusional antics as a jewel thief (from his previous life). This to his detriment worsens his mental state even faster. After some time passes, he begins to rely on the robot & treat it like a human companion. He gets to the point where he rejects his own daughter in favor of the robot who he sees as a genuine being. After stealing the diamonds from his suspicious neighbor, his paranoia begins increasing & he begins creating fantastical ways of avoiding detection. In the end, in order to protect him from himself, the robot convinces him to delete it's memory in order to cover up evidence. The robot recognizes the fact that it can no longer be of assistance to Frank who now needs constant supervision in a secure setting.
Symbolically the robot represents who we wish we could be. We wish to erase our pasts or start fresh but we don't have this feature as human beings. Dementia sufferers can't restart or go back to a point where they can think clearly. Dementia slowly worsens until a person dies. In the end Frank had to go to the nursing home because he was losing control of his own actions. In the final shot, Frank acknowledges to himself that his robot just like the robots that surround the other elderly people in the nursing home was nothing more than a machine whose primary function was to improve his health (even if that meant deceiving him). Brilliant but very sad movie. 8/10
If insane outnumbered sane, would sane then be considered insane?