After Carlson killed candys dog, what did it make Candy and some of the other workers on the ranch realize about themselves or their futures?

The death of Candy's dog reminds the men on the ranch that they're alone..... and that because of the way they've lived, they likely will lack companionship in their older years. Candy's sole companion was his dog. He had no family, no wife, and no children, and like him, many of the other men realize they will be facing that same kind of loneliness some day.