Question: What is the date of death of Philip Zaleski's mother?
Sentence (from "Philip Zaleski"): In addition, he is coauthor with his wife Carol Zaleski of "The Book of HeavenPrayer: A History", and "The Fellowship: The Literary Lives of The Inklings J. R. R. Tolkien, C. S. Lewis, Owen Barfield, Charles Williams."
Relevant evidence: No