more help please

Willy wants Biff to be successful, and return to the young man bursting with potential as he was when he first worked for Bill Oliver. Willy has, like the fathers he represents, placed all of his hopes and dreams on the success of his eldest son now that his own dreams have vanished. Sadly, Biff will be no more successful than his father, and this realisation is crippling for both of them.

Biff stealing Bill Oliver's pen resurrects his weakness for stealing which appears to be his fatal flaw. Both brothers seem to have an unconscious need to take what is not theirs (Happy takes others' girlfriends).