Who is Shepherd from Running from Safety: An Adventure of the Spirit and what is their importance?

Shepherd appears at the beginning of the book as a stranger offering a ride to Richard, who is headed up the mountain for another paragliding adventure. At first, Shepherd comes across as a writing fan, but he soon reveals himself as a teaching angel. He is the one who reminds Richard of his promise to 9-year-old Dickie to tell Dickie about the important lessons he has learned in life.