Loneliness is a theme that runs like a thread through the entire story and is a quality shared perhaps by most of the characters. Migrant workers are often men who have no roots, who drift from place to place to survive and have little stability in their world.
In Candy's case, isolation and loneliness stem partly from the disability caused by his having lost a hand. But his elderly age may be an even more important factor. His dog is his best friend—hence, his extreme reluctance to have the dog put down, even though it's obvious that the animal is suffering and that euthanizing him is the most humane option.
The dream of having one's own homestead is a kind of beacon in the night to George, Lennie, Candy, and Crooks—a solution to their displaced status, even in a world where instability and rootlessness are normal and expected. Each of these men is the Other for a different reason: Lennie because of his developmental disability, George because he isn't free to lead an independent life and must take care of Lennie, Candy because of his age, and Crooks because of his race. The dream of living "off the fat of the land" is alluring but mythical. It represents salvation to these men who wish to escape their isolation and to bond with others who have similar problems. Because of age and a physical handicap, Candy is at least as alone as George, but George's youth gives him more to look forward to even after the tragic conclusion of the story.