Complex sentence: Ivor Jackson, who was still slumped in White's Toyota, heard Dorothy Ryan open the door of the car and say, "Oh, Ivor..." before attempting in vain to reason with her son.
Split into simpler sentences: Ivor Jackson, who was still slumped in White's Toyota. He heard Dorothy Ryan open the door of White's Toyota and say, "Oh, Ivor..." before attempting in vain to reason with her son.