Why does Karim think Maha left him many questions and few answers?

Maha is a twelve-year-old girl from Beirut, Lebanon, whom Karim meets while trying to find her dead sister Nada. She and her baby brother Jad are the only surviving members of their family, following a catastrophic bombing. Karim doesn't understand her stress and her adolescent angst. Maha is deeply devoted to Jad, doing anything to keep him with her—the entire reason why she sets out on the dangerous journey to Chlifa is because she wants to make sure that they don’t get separated through adoption. She puts up a strong, rebellious facade, smoking cigarettes and secluding herself from the people around her, who see her as a troublemaker. By the end of the novel, it is clear that her tough facade is concealing her survivor's guilt.