what does biff reveal about happy? what does he reveal about himself?

Biff tells Happy that he did a terrible thing. Bill Oliver did not remember Biff, and walked away when Biff approached him. Biff stole his fountain pen, though. Biff insists that they tell their father tonight to prove that Biff is not lying about his failures just to spite Willy. Happy tells him to say that he has a lunch date with Oliver tomorrow and to prolong the charade, because Willy is never so happy as when he is looking forward to something.