The Stranger

As I was reading The Stranger I was confused about Meursault, was he really feeling bad for his mother and did he really not care that his mother had died? He kept his feelings to himself instead of sharing it with anyone else. He did not show any change in emotion when he saw his mother dead. Was he in shock of his mothers death or was he just careless? Meursault spent his whole Sunday just describing the appearance of everything around him to himself, he recalled the roads, the families on the street, the kids crying, etc. Meursault did not object to write Raymonds letter even though he knew his neighbors detrimental plan for the girl. Is Meursault behaving like this for a purpose or he is actually dispassionate? I am curious to know what happens next.