William Wei, the character of Koko, and lying

In the story of William Wei, the character Koko is the woman who William 'falls in love' with. Their relationship initially begins on the phone where she tells William that she saw him at a party and that his friend gave her his number because the friend was worried about William.  When she confronted William about his daily routine he lied to her, which started the relationship upon lies.  Lies would also become a main part of this story.  As they continued talking William asked her what she looked like and she initially lied to him saying she was an old woman and was hooked up to a respirator.  Their relationship began to grow and for all we know based on the information in the story, this is the first woman that William truly gets to know without sex being involved.  It seems as she changes his ways a bit because he doesn't objectify her as much as the women he discusses at the beginning of the story.  He isn't as interested in her looks and also calls her modeling work for her clothing line artistic and doesn't just "drool" over the body shots she has on her website.  The character of Koko is also a confusing character that also lies a lot and also has problems with drugs.  The first point where she confused me the most was when she tells William that she is a sociopath.  This confused me because I don't think I've ever heard of a sociopath that self-diagnoses themself as a sociopath.  Also, almost the entire time she was actually with William they are on drugs.  She keeps pulling out more and more drugs and offers it to William.  Finally, her lies all catch up with her at the end of the story when she is on the phone with Douglas and then begins to cry and leaves William to say her mom has cancer of the bowels.  This is when we know that she is lying about that and even William realizes it.  This story ultimately confused me at first but rereading it made me realize that it is about lies and drug/alcohol problems.