Who is Horace from War Comes to Willy Freeman and what is their importance?

Horace works for Sam Fraunces and is about the same age as Willy. The first time they meet, Horace is transporting a wagon of wood and the two become friends. Unfortunately, Horace believes that Willy is a girl and becomes angry when he finds out that she's misguided him. Horace, however, quickly forgives Willy and is saddened when she leaves to see her mother.