Dallas is your shitty older brother. He does stupid stuff, he smokes, cause minor crimes, probably like steal or something like that, he is delinquent, he is always out waaaay past curfew, he just isn't a good example for you. While Dallas is 17 years old, your his younger sister, your 14 years old. Even though he is all bad, he does get tough around you a would be a little mean and rude- he wouldn't go overboard.