KEANE HAD A DAUGHTER
Although there are good arguments for whether keane did or didnt have a little girl i believe that he did . A cruel twist of fate took his daughter from him , and we see this at the end of the film where he takes his eyes of keira for the same interval of time but she returns safely to him .
Additionally in mcdonalds he recoils for a second when he realises he has left the girl alone BUT she is still there when he returns to his relief. He starts to understand that this is something that happens in the world all the time but yet he tortures himself over it .
I think his daughter got lost and was snatched while visiting him in NYC - his illness had resulted in estrangement and divorce (as happens often in this situation)
Keane sees a woman abandon a child for 2 days (with a man she clearly knows is ill ) while he only took his eyes off his little girl for a minute and lost her . Keanes reenactment of his daughters disappearance finally confirms this shattering truth - this was not something compelled to constantly happen to him over and over again (like it does in his mind) but a shocking random incident in a cruel world.
Keane has survived through medicating himself with alcohol and drugs and attempts to return to the real world with work but is rejected again and again . I think keane was a good man in agony inventing scenarios surrounding the abduction to relieve his pain to keep him from totally collapsing.
The final scene gives him the chance to finally apologise to his daughter and to say goodbye , but not to his illness and pain which will haunt him forever.
Fantastic film - great performance .