If you buy into the theory that this movie and the Fast and Furious franchise are indeed connected, there are some parts of Han's character that make sense in hindsight:
Han is abusive and a complete jerk to Virgil, but is still there for him after he attempts suicide, showing he has some value of family.
Han drives an old muscle car (a 1965 Ford Mustang); Dom comments in Tokyo Drift that Han was into muscle cars when he knew him.
Gisele comments that she can tell Han is an ex-smoker; Han smoked heavily in this movie and was rarely seen without a cigarette.
