I'll try to make this as short and clear as possible.
Background
I've known this person for about 8 years but I wasn't as mature and perceptive when I first met him as I am now.
We used to talk, play video games and hang out a lot, I stopped talking to him around 2 years ago because he was really mean to me and said something hurtful. During the next year every time he talked to me I just responded in a polite way but didn't make much conversation.
I don't remember exactly how this happened but I explained to him why I had stopped talking to him and we had some serious conversation where he said that he was sorry and that he had been visiting a psychologist because he sometimes does and says things that hurt people without noticing (that's what he said.) I explained to him that we were not friends anymore, at least not as much as we used to and that if he wanted us to be friends again he had to show me that he was actually different.
Now we talk from time to time, we've played video games together again and that sort of stuff. The thing is, I've noticed plenty of his old behaviors and I don't think he's changed at all.
My goal
I want to give him sort of an ultimatum where I point at his bad habits and make him notice that if he doesn't change he is not going to ruin only our friendship but probably the ones he still has.
Plan B
If he doesn't change I want to cut off any relationship with him completely. I know this is going to hurt him because many others friends have left him before me and I'm one of the remaining few he still has, so I want to make him the easiest way for both of us.
Things that make me tag him as toxic and I'd like him to notice:
- 8 of 10 times he talks to me he wants something from me. And if I don't give him what he wants he gets mad and says things like "you really gonna let me down?" or "all right you ass".
- He believes he is always right, it's imposible to change his mind, he won't accept other opinions as valid, he will call you and your opinion stupid and won't shut up until you "accept" he is right.
- I noticed I had never heard anything good about him from anyone, not even once. Not from professors, not from friends, not from my family members that have met him. And whenever I hear someone talk about him they refer to him as annoying and don't want him around.
- He makes fun of others and makes less of them, their opinions (as I said), achievements, jobs, anything. Also he gets mad if someone makes a joke about him. One time he got really mad because someone called him humble in a sarcastic way and everyone laughed.
- I don't want to bring him along with other friends because I'm scared they will blame me for bringing him if he does/says something bad and I won't be able to be in anyone's side.
Any advice will be highly appreciated.
Note: As I expected I received answers saying that changing his behavior is not on me, that is true and I know it. Please notice that I'm not asking how to change him but how to make him realize he is toxic and that toxicity will not do him any good and he has to change for his own sake.