What does the murder of Hassan do to the plot development of the primary conflict between Amir and his own guilt?

The murder of of Hassan and his mother leaves Hassan's son, Sohrab, without parents. Rahim Kahn informs Amir of this and tells Amir that, "there is a way to be good again". Amir finds a little redemption for his guilt by going to Afghanistan and bringing Sohrab back to America.