It's rather depressing to go back and watch the old captain's logs, as Chris has consistently attracted both the worst sort of people who wanted to see how far they could push him, and the most charitable types who falsely believed they could protect him from himself and provide a semblance of structure in his life. When combing through the pre-trans, pre-fire, Bob-still-alive years, it's very clear that Chris may still have responded positively to sustained mental health efforts instead of sequestering himself further in his own world - a classic and naive self-medication tactic. By no means is he an innocent victim in all of this, but as his material and mental state declined the chances for him to get legitimate help and the potential efficacy of such help had dwindled in kind.
The thing about Chris, and many high-functioning autistics, is that they are fundamentally helpless, that is, they terrible at helping themselves. Instead of learning how to use his imagination and intelligence to define realistic goals and gradually achieve them despite failure and setbacks, he was left alone to indulge in his pet fantasies. Instead of being guided towards integrating into society and earning respect from others, he latched onto Bob and Barb because they were the only authority figures he could consistently trust. You can see by his devotion to Bob's conservative talking points that he was very much looking for approval from authority figures. If this behavior could have been transferred to people outside his immediate family, he would probably have been capable of holding down a job and even putting his computer skills to use. People forget that Chris did write and maintain his own website, a feat which seems laughably rudimentary nowadays, but would have earned him a respectable paycheck if he kept at it.
Chris does obviously present elements of sociopathy, narcissism, BPD, and what have you. It's amusing to see schizophrenia speculated about as well. Yet he has never developed along a trajectory that suggests the typical, medical course of a single mental illness or personality disorder, so much as he has simply tried to navigate the world given what little he knew about it, compelled by the same needs and desires we all have but without the machinery required to really make it work, in a way that the payoff is being respected and well-regarded by others. When you can't truly fulfill your desires, you do the only other thing you can, which is to compensate. I believe that most of his neuroses and perversions are just the sad result of normal people not having the patience to deal with him past a certain point, coupled with Barb and Bob's inability to pry him away from his fantasy world so that he could acclimate himself to the real world and define himself through his relationships with others, rather than through purely imaginary means.