I think the reason they see things that are not there is because their brain is so consumed of alcohol .It distortes their reality. my AH kept mentioning a guy named josh in our bedroom. I have no idea who josh is, and I sure did not see him in our bedroom, but my AH did. If I asked him now who is josh, he would have no idea what I was talking about. I don't know if well ever know why they see what they see, because when their sober they don't remember anything. It is scary. Maybe they create a different reality because they can not deal with their own. just a thought.