Who is The Old Rancher from Cities of the Plain and what is their importance?

The Old Rancher gives Grady a ride while it is pouring down rain. He is on his way back to the White Lake after learning that Magdalena has been murdered. The old rancher is on his way home to take care of an animal that is hurt. As they travel, the old rancher tells Grady about his love for his wife, not knowing that Grady has just lost the love of his life.