Certainly the most important relationship between male characters with regard to this question is that between Willy and his friend Charley. The way this relationship works as a foil is by the comparison between the success of Charley and of his son, Bernard, and the failure of Willy and of his sons. Throughout the play we are shown that when they were growing up, Willy encouraged his sons to mock Bernard because of his studious and non-athletic nature. However, he is confronted with Bernard's success as he turnes into a lawyer who is going to argue a case in front of the Supreme Court. Willy is surprised by the fact that Bernard didn't even mention it. When he expresses his surprise to Charley, he responds by saying:
He don't have to--he's gonna do it.
Thus the dreams of the Loman's which are always deferred and never come to anything are contrasted sharply by Bernard's character, which is based on action and hard work. Likewise, the success of Charley is emphasised by the way that Willy always comes to him for loans, and the job that Charley offers Willy. However, Willy is unable to accept this job as it would mean acknowledging his failure.