Thin hair means that he is a highly sensitive soul, and that his feelings can be easily hurt.
Brian's thin lips say that he has trouble verbalizing how he feels, like Kevin. That doesn't mean that he doesn't want to express himself, though. It just means that he will always have to work on being able to get things off his chest.
Brian's uneven ears say that he is a charmer who has an amazing sense of humor. He's also equally skilled at making all sorts of people around him feel totally at ease.
High cheekbones say that Brian has a very high sense of morals. Don't expect him to be easily swayed from the good, honest path that he's carved out for himself.