Grayson already has compassion, way more than the rest of the Millers. He just do things that seems practically possible for him. Manhwa didn't represent it clearly but the fire was way more extreme. Even the rest of the firefighters do the same thing that Grayson did. Actually, the they have always done that to Dane and will do the same in the coming chapters. Its easy to shout on others.

my guy, he has thing called compassion, learn from him ( =_=)