He clearly hints that he just doesn't care. He probably doesn't think he can do anything about it or care to. It's a disinterest based in selfishness. Evidence of this attitude is given all the times he remarks on his pay. Now duh he can't make use the money if the planet's gone but let's pause and use our noggins a little. Does he know just what moment the planet will cease to sustain? Doubt it. Also, just try to put yourself in the shoe and imagine why someone would feel that way. Someone disinterested in the greater picture of things and rather choosing to worry about themselves with the little time they might have left? Not very hard to fathom