I (28M) am thinking of ditching a toxic autistic friend (29M) who I have known for 14 years and had enough of.

***EDIT: Check one of my main comments below for details on how I have attempted to communicate with my friend in the past.***
In 2006 I was in secondary (or middle) school and had hardly any friends, and found it difficult to relate to others in part due to having Asperger's syndrome. Upon moving to a new school building I made friends with two boys in the year above me who also had Asperger's, thinking that it could really help my social life. One of them (who I'll refer to as L) has always had a tendency to be rather abrasive with people, trying to assert intellectual dominance, putting down people for showing opinions that don't align with his, becoming increasingly vitriolic when people try to justify their viewpoints (this could be anything from political views to game console preference) and showing signs of bitterness when other people are having fun or talking about enjoyable aspects of their lives. Recently I played some games online with L and couldn't help but notice that he still has these tendencies, and he made several remarks about me which sounded critical or insulting, almost as though he was trying to make me out to sound ignorant and not know what I was talking about.
Some examples of unpleasant memories involving him include:

• Telling me that "sometimes when you talk it's like listening to Father Ted" (for those who aren't aware, this is a sitcom about several priests who all do stupid things)
• Knocking me for academic achievements - e.g. saying "dammit, you've beaten me already!" when surpassing his own, or saying "I got that!" when comparable with his
• Showing signs of being bitter when mentioning advances in my social life - e.g. saying "you just wanted to drop that in, didn't you?" when mentioning my girlfriend
• Trying to spin things I say to make me sound ignorant - e.g. "you do know Europe is a continent, not a country" in response to me saying that if I had to choose between identifying as British or European, I would choose the latter, purely in terms of cultural identity and that Britain does seem different from many other European countries in many ways
• Being unhelpfully critical when in need of help or advice - e.g. when I once lost my iPod in school, he gave me a lecture about why it's not the best music player and why I own one in the first place
• Saying that "anyone who owns an Xbox is an ******* who can't unglue themselves from the television" knowing full well that I owned one at the time
• Saying "how on Earth could you afford this?" when I admitted to him that I had a problem with ordering too many takeaways at university
• Recording a video of me dancing (slightly maniacally looking back on it) when I was 17 and having fun with other people at a high school prom, whilst he was sitting alone by himself and not speaking to anyone.
• Bringing up examples of impulsive things I've done in the past yet added to my character building yet which he thinks are stupid

After spending 14 years on and off slowly dealing with this and saying nothing, I am strongly considering cutting him out of my life completely as his company is emotionally draining, and it is questionable how much I enjoyed his actual company in the first place. The only things we've really had in common are the fact that we both have Asperger's and that we both like video/board games. I see him very rarely these days (once every couple of months or so) and deliberately so, but when I do see him I am frequently reminded of why I feel so relieved when he is gone and why I felt as much when he left school before I did. In fact, I unfriended him on Facebook thereafter but he re-added me a year later (though I never communicated with him why I did this).
Another of my really close friends (who is neurotypical and will call J) often spends time with L, but when he describes his interactions with him, his descriptions are mostly negative. When I met up with J recently he said that he only really spends time with L because he feels sorry for him, because he has quite a few interpersonal difficulties and hardly any friends and that it's like an act of charity. Apparently L gets frustrated when people "flake away" from him and don't invite him to things, but it seems like he is completely unaware that his behaviour is driving people away.
I find it really sad that L has shown very little personal development, and acts and speaks in a pretentious way despite having relatively little going on in his life to show for it. He has often looked for opportunities to be critical of me, even though my academic achievements and life experience have significantly surpassed his own. To put this into context, I have been consistently getting top grades in school and at University, now a mature student studying at Oxford after having spent a few years as a high school teacher building my social skills, travelling to America and the Philippines (where my girlfriend lives) and pushing myself to do things that many people with Asperger's would deem incomprehensible. On the other hand, L peaked academically when he was 16, and now has a low grade at a poorly-ranked university, was made redundant from one job and has not been given a promotion or pay rise in 5 years at his current job, has never had a girlfriend or mentioned any positive developments in his personal life and gives plenty of "non-reasons" not to do things when people suggest positive strategies for him to improve his own life.
I'm know precisely how difficult it is to socialise as someone with Asperger's (and several mental health problems) and I am sympathetic to L because these things undoubtedly play a role in his own life. Looking back on when I was younger, I could tell he had a volatile relationship with his family (especially his mum) and that probably led to his behaviour becoming part of some sort of defence mechanism. The major difference between myself and L, however, is that I have taken it upon myself to analyse what isn't going well in my life, and I have spent several thousands of pounds out of my own pocket on professional help to help me to gain some emotional insight and intelligence. I feel much stronger as a person as a result of having done that, but it seems unclear to what extent L has attempted to address his own problems and if raised it strikes me that he would simply deny them or try retorting. When I've tried raising these things with him before he has simply said "I know" or retorted against me.
To this end, I am thinking of telling him that I am cutting him out of my life completely, explaining to him what I have explained above and why his behaviour makes him fundamentally unenjoyable to be around. It would be a bitter pill for him to swallow, but I feel like it could be doing him a favour given his difficulties. From what I gather, most people he has known over the years have stopped inviting him to things and hopefully if I elucidate my frustrations to him it might give him some detailed insight as to why people don't enjoy his company all that much, and give him some pointers on how to improve himself as a person. I know how much anxiety that ambiguity about social situations can cause someone with Asperger's, which is why a part of me feels like voicing these concerns to him would help him to understand himself better. The other option is just to flake away without making any severances, which is what most people would do out of not wanting to start conflict or feeling like it's not their responsibility to fix others - but this wouldn't help L so much and would potentially leave him bemused as to why people don't want to spend time with him.
I am thinking of asking J if I can join him and L the next time a social commitment takes place, and using it as an opportunity to voice all the concerns I have mentioned above if L says something that touches a nerve, and officially tell L that I don't want anything more to do with him because I don't enjoy his company. I could do with some pointers on how to do this effectively.
TL;DR: I am thinking of formally cutting ties with a friend of mine with Asperger's who I have known since secondary school and has shown very little personal development including being unhelpfully critical of others and showing bitterness.
EDIT: "I'm not going to pretend to know..." replaced by "I know precisely..."


Source.