Who is Henry James Ironheart from Cold Fire and what is their importance?

Henry James Ironheart was Jim's grandfather. He and Jim's grandmother raised him after his parents were killed at the Dixie Duck. When Henry finds his wife dead at the bottom of the stairs, he blames his grandson, believing that Jim pushed her to her death. As a result, Jim leaves town, returning only after Henry suffers a stroke. Unfortunately, Henry's slurred speech leads Jim to misunderstand what he tells him, and Jim believes that his grandfather has called him a murderer. Jim then runs away and never returns.