Father son relationship

for willy to win, he needs biff to embrace him --> biff loses his what makes him biff
for biff to win, he need to cut off willy --> willy loses everything he worked for
there is 1 winner and loser
but the winner wins at such a cost he also loses
in the end of play, biff wins (willy dies), willy thinks he wins (misinterprets biff's tears)