Malcolm interacts with nobody but Cole, and when I say nobody, I mean not a single soul.
I understand that Malcolm is lonely and possibly doesn't have many friends or anything, but this means that he had literally zero interaction with strangers on the street, shop owners (if he ever wanted to buy something), people he knew (if he saw someone he knew, they would've never said "hi" back), and was basically invisible to the entire world. Thinking realistically, I don't think a regular person would get through a few hours without realizing that something was really, really wrong if they were invisible to the world (i.e. dead). Are there any explanations for this, or does M. Night just expect you to believe that Malcolm didn't realize that the world (other than Cole) didn't acknowledge his existence in the slightest?
PS - I am aware that Malcolm senses something wrong in his relationship with his wife, but, as I've explained, him not being alive means that literally no one realizes he exists and "sees" through him.
PPS - Additionally, how does he throw a brick through his wife's window (when she's talking to that other guy)? Or is it not him at all?