Letter's of Note in 2012 reproduced the following letter from author Ken Kesey (One Flew over the Cuckoo's Nest) from Co-Evolution Quarterly. It was written after the tragic death of Ken's young son Jed in a bus wreck on the way to a wrestling tournament.
Addendum
Recently Zane Kesey (another of Ken's sons) posted the original letter on Facebook. And notably, the postscript differs in Zane's version of the letter. In Zane's version of the letter, Ken describes checking a Wendell book to confirm the spelling of his name, and the book falling open to Berry's poem "To Know the Dark"
Zane periodically shares his own reflections on this heartrending episode himself here on his Facebook page.