Casper mention during the scene in the attic that, as a young boy he wanted a wooden sled around winter time. He begged his father to buy him the sled, however his father was concerned as Casper didn't know how to ride it. Then one morning when Casper came down for breakfast he found the sled in the kitchen. Casper took the sled out and went sledding outside during the cold winter. His father came out said "that's enough!" but Casper couldn't stop as he was enjoying it. Then it was late and it was nighttime and soon Casper was sick from pneumonia.
McFadden tried to get medicine and medical help for Casper but it was too late as Casper was dying from the illness. Shortly after Casper died he returns to his father as ghost. McFadden would later become frightened by his dead son as a ghost. Through several newspapers he told his story about he was haunted by the ghost of his dead son, but none of his statements were believed. McFadden would later decide to use his scientific genius to invent a machine that can make a ghost turn back into a human who would be brought back to life. He called the invention the Lazarus which is named after the man in the New Testament who was raised by Jesus from the dead, using a "primordial soup mix" that he invented. His laboratory was located in the basement of Whipstaff Manor from where he conducted his experiments. McFadden was soon arrested by local authorities after nearly completing his machine and was sent to an insane asylum.
It was unknown when McFadden died but he is mention by Amelia Harvey, Casper's friend Kat's mother who has become one of heavens angels. Amelia told Casper that his father won't forget how he used the machine to bring back Kat's father Dr James Harvey from the dead and that he fullfied his greatest dream to turn a person from a ghost back into a human being. She also makes it clear that his father is very proud of him. Casper would later get his dream in return by becoming human himself but it was only for that one Halloween night so that he can dance with Kat.
- The Ghostly Trio have mention Casper's father in one of the deleted scenes on the DVD.
- An old newspaper article which has the picture of McFadden on it is picked up and read by Kat during the attic scene. This was probably one of the newspapers that McFadden told his story to the media about Casper.