What is the subject and theme for the passage a Dark Brown Dog by Stephen Crane

The story, "The Dark Brown Dog", is about a boy who came upon a dark brown dog and it ended up following the boy home. the boy tried to make the dog run away but his efforts were useless. the boy brought the dog home to his family and they decide to keep him. Over time they form a bond. when the dog is not in sight of the boy it gets abused and that abuse haunts the dog and he has nightmares through the night. the only thing that makes his nightmares better is the boy. so basically this story is about how a boy and his dog build up a relationship but the people around them affect the dog