How do the relationships between fathers and sons in The Kite Runner affect the events of the novel?

The circumstances of Hassan's birth, antecedent action in
the novel, directly or indirectly drives the events of the narrative. His guilt over
fathering Hassan but not claiming him determines Baba's relationship with Hassan and
also with Amir, the son he does acknowledge. Baba is especially kind and gentle with
Hassan, a mere servant, for reasons that Amir cannot understand; in contrast, Baba is
demanding and distant with Amir. Baba's treatment of his two sons creates in Amir a deep
insecurity and jealousy that leads to his two betrayals of Hassan, his friend. The
subsequent shame and self-hatred almost destroy Amir.

The
relationship between Baba and Amir changes, however, and the change directs events once
they immigrate to California and make a new life. Baba does love Amir, which Amir comes
to realize, first during their dangerous escape from Afghanistan and later when he
watches his father struggle to support them. Living in poverty brings them together as
they work side-by-side to eke out a living. Baba's love for Amir is further demonstrated
when he acts to help Amir realize his marriage to Soraya. Because the relationship
between Baba and Amir has changed so profoundly, Amir and Soraya make a home for Baba
and care for him with great tenderness while he is dying.