My friend returned from Afghanistan and his attitude regarding Afghans changed, why?

He's saying "compared to them, we are animals", he used to think that Afghans were sub human barbarians, he spent time with Afghans but won't give much detail, he just tells about how badass afghans are, even the kids go barefoot in sub zero temperatures. He also became interested in islam and has a copy of koran. Why this change of attitude?