It's always true: the life of one affects the lives of many. Here, John Sullivan (James Caviezel) is not recognized by the woman he loves; there, the same happens with George Bailey (James Stewart).
In a way, here the son also goes back in time and changes the lives of his parents. Those changes are visible in the photographs, and, in the end, his family - and his house - are different... for the better.
mentioned in dialog
a poster in the fast food
DVD and video case are shown in a video store.
It is listed as one of the "sweded" movies. Also, video case and poster are shown.