At the end when Ben Affleck sees his parents again he's wearing a dark green shirt, but on the very last shot of him he's wearing a white shirt.
Steven says that Tommy disappeared when he was only seven but later in the episode he says Tommy turned up missing in 1982 and that Tommy was only six at the time.
Mrs Thompson says their son disappeared in 1982 when he was 6. Their son turned out to be Ben Affleck, who would have been 9-10 in 1982.