I'm not at all offended :) It's not a well understood thing from what I understand, and of course it varies. It's exacerbated by things like movies, but I feel like I actually have the exerpience to clarify, so I did.
That situation with your father sounds so stressful. My brother in law was schizophrenic and the different was 9very simplistically) explained ot me that multiple personalities are all inside your head, but schizophrenia was hearing voices from outside your head. In my BIL's case, he would see things outside of himself that spoke to him and he became terribly paranoid. He's spent some time homeless because he was afraid to go back to his government assisted housing because of his delusions. It is a sad thing and I just feel very fortunate that I was able to have the right support to deal with my own issues in a way that didn't destroy my life.