Reagan Hannah Mendes is 15 years old and he has a brother who might be a little bit Famous... Shawn Mendes might be her brother... Fine He's her brother. It's not easy being his sister. Reagan has a hard life. Not seeing Shawn on my their sister Aaliyah and their parents. It's hard for her. She misses her older brother to be there for her. Shawn is the overprotective type of awwbrother. He's not easy.