in ch.25 what wonderous small thing gives amir hope? Also how does amir show his loyalty to sohrab in the books finale scene? what does his actions reveal about him?

Amir is at the hospital, waiting for Sohrab. He finds a bedsheet and kneels on it to pray for the first time in over fifteen years. He mumbles the phrases of prayers he still remembers, his belief in God suddenly renewed. In his prayers, he begs God to let Sohrab live; he will do anything to ensure the boy's safety, saying, "My hands are stained with Hassan's blood; I pray God doesn't let them get stained with the blood of this boy too." Sohrab gets better and lives with Amir and Soraya in San Francisco.

He bought one and brought it to Sohrab. He told him that Hassan was the best kite runner he had ever known and asked Sohrab to fly the kite with him. Sohrab remained silent, but Amir knew what to do; he ran as fast as he could to launch the kite. As he stared up at it, he noticed that Sohrab had followed him and handed him the string. Sohrab soon gave it back to him. They stood in silence once more until they noticed a green kite closing in on theirs. When the kite came close enough, Amir performed Hassan's favorite kite-fighting trick, "the old lift-and-dive" as Sohrab watched, mesmerized. The green kite fell out of the air. When Amir looked down at Sohrab, he witnessed a half-smile steal over Sohrab's face. He asked, "Do you want me to run that kite for you?" Sohrab nodded, and Amir told him, "For you, a thousand times over." Amir ran among the children, after the kite.