The source for this information is in Ardell Sheridan-Castellano's book Divine Intervention and a
Dash of Magic Unraveling the Mystery of the "The Method". The author is obviously Richard Castellano's wife and she says that a mysterious visitor came to visit Richard on set one day, but that Richard didn't introduce him to his wife and Richard basically told his wife to forget about it.
Apparently, it wasn't until December 16, 1985 that Castellano's wife learned the truth and Richard admitted that Paul was his uncle.
http://books.google.ca/books?id=OzleKlCP...ano&f=falseThis is the link to the information it is on Page 183-184.