In The Death of a Salesman, how does Biff as a football hero embody his father’s dreams?

Willy , in the play "Death of a Salesman," is the
representation of a man in search of the American Dream.  One aspect of the American
Dream is to have a son who is smart and athletic.  Willy did not have the advantage to
become a football player, but in his son's athletic abilities he sees a chance to be a
part of that piece of the dream.  He is unable to see the reality of his son's lack of
effort in school and issues.

Willy follows the son's
actions and muddles over them making his son the super star he himself never was. 
However, Willy is so wrapped up in the dream of what he wants his son to be that he can
not see who his son really is.  Because Willy can not come to terms with his own role in
life he lives through his son's actions.