Complex sentence: The film is dedicated to Will Gaffney, an actor who was David Morse's stand-in and killed in an on-set accident for a scene Morse was not available for due to a family illness.
Split into simpler sentences: The film is dedicated to Will Gaffney, an actor who was David Morse's stand-in. He was killed in an on-set accident during a scene in which Morse was not available, due to a family illness.