It's an interesting thing with cows. I'm sure most of us do some heavy daydreaming about vacationing or winning the lottery, or even spending time immersed in fictional worlds from books, tv, or our own making in our heads when driving or doing tedious work tasks.
For most people, these daydreams stop when they have to think of something relevant to the moment, or when socializing, but cows like Russ are living the daydream so intensely that it starts to become their reality regardless of what is going on around them. I feel like any conversation anybody has with him, in his head is just "ahhh yes hookers. Hookers are great. I'm great." He lives in his fantasy world where he is the super coolest stud and all women want him, and whenever he doesn't get his way (aka get some poon) its the fault of the evil chads and mocha men for brainwashing women into liking them and hating poor old Russ for being disabled, even though he is better looking and far superior intellectually.
I don't think there is anything that can pull him out of this mindset at this point. It is neurologically coded into his brain to the point of no return. It's farfetched but if he continues to deteriorate there could be a dimensional merge where he believes he is actually banging Taylor Swift and is adored by the world over. I don't think this is where the story will go but the man is insane, so who knows.