His younger brother's reaction may involve some psychological factors. For example, self-comfort: people often seek comfort by comparing their own situation with others. When we see our relatives experiencing misfortune, we may feel that our own situation is better than theirs, thus producing a feeling of self-comfort. This feeling makes us feel luckier than them, and therefore we feel more comforted.
RE: One Thousand and One Nights: The Story of King Schahriar and his brother King Schahzaman: Part Two