What does Amir give Sohrab? Why? How does Amir try to alleviate the guilt Sohrab feels?

Amir gives Sohrab the Polaroid photo of Hassan and Sohrab.

Sohrab asks Amir if God will put him in hell "for what I did to that man [Assef]" (24.75). Amir tells him of course not, and gives Sohrab a vague history of his and Hassan's dealings with Assef. Sohrab cries for a little bit. He feels "dirty" because Assef sexually abused him. In fact, Sohrab doesn't even want his father and mother to see him, because he feels so sinful. Amir comforts him.