How does Garvey challenge the audience members' feelings towards Cole’s behavior?

While Cole is being escorted out of the room in handcuffs, Garvey asks his father the date of his son’s birthday..... Cole's father doesn’t remember. In doing this, Garvey is exposing Cole's relationship (or lack of) with the man who is supposed to be the most influential man in his life. The "audience", as a result, gets an intimate look at Cole's father, as well as his treatment of his son.