What would help confirm whether this is Aspergers is the presence of some of the more subtle symptoms of the disorder such as showing unusually rigid, repetitive patterns of behavior such as eating the same food every day, or placing himself on a rigid, unchanging schedule and showing a great deal of ANXIETY
and worry if this is disrupted. In many cases, but not all, people with Aspergers show exceptional abilities in a narrow area of skill or knowledge e.g., knowing all of the names and life histories of all of the U.S. presidents, with easy recall.
The other hypothesis is something called a personality disorder. He likely has a mixed personality disorder, as most people with the 'disorder' do, rather than a single, 'pure' disorder. There are about 12 such disorders; You can Google DSM Personality Disorder and look at whether he shows an admixture of a few symptoms from each of the following: DSM Avoidant Personality Disorder; Schizoid Personality Disorder
; Antisocial Personality Disorder, Narcissistic Personality Disorder. If he has odd, peculiar, truly eccentric beliefs about the world, then also consider Schizotypal Personality. My own thinking is somewhat focused on a mixture of Antisocial Personality Disorder, and Schizoid Personality or Avoidant Personality disorder.
I can only give you leads because without spending a hour or two with this guy, on days spread 2-3 weeks apart, it is really impossible to assess and diagnose what is happening here. But the botXXXXX XXXXXne is that he will likely NEVER change much, though with effort, he can learn more sophisticated social skills, which he lacks. He probably will never 'learn' empathy, or understand how he comes across to other people. Whether he has Asperger's or a mixed personality disorder, he will be much more prone to having episodes of depression than other people from time to time and he can be encouraged to see his doctor or a clinical psychologist if this happens. But as a rule, he will not see a 'need' to consider learning more about himself or changing his behavior; though he might be willing to talk to someone if something major in his life 'falls apart'.
I hope this information is helpful to you. This does sound like it could possibly be a case of Asperger's Syndrome. Please let me know if I have overlooked any aspect of your original question. Please click on the green Accept button at the bottom of the screen. Thanks.