What news does Arn get about his sister Chantou?

In Chapter Four, one soldier from their old town comes to the camp and offers information about his family if Arn will give him his food; and tells the girls they can have messages sent to their family if they come into the woods with him. Arn gives him the last of the rice he’d saved, and gets a letter from Chantou in return, learning that she and Maly are together in a mountain camp and working hard.