First of all, you're making a lot of assumptions about how this friend feels that, unless you're the best damn psychic I ever met, you couldn't possibly know. For example, how do you know he doesn't give a shit about what went on? I would say it sounds like exactly the opposite is true.
Now, this is stereotypical, but it comes straight out of Men are from Mars, Women are from Venus, so blame John Gray if you don't like it. Men, you see, are not as good at the emotional stuff as women (usually). Women have this need to talk about their feelings and what happened and blah blah blah, whereas men would rather it just all be over without all the emotional bullshit going on. From your perspective, you're thinking "OMG, we've never talked about it and resolved these issues!" but from his perspective, he likely feels like "Whew... glad that's over." It's probably not that he doesn't care, it just that he's not interested in sitting around dissecting his emotions and yours.
He could very well be sorry for how things went, but would rather not talk about it. Even if he realizes that he treated you badly, it may be that he's embarrassed by that and so doesn't want to bring it up again (emotions are often embarrassing things for men).
So what should you do? Send him an e-mail explaining how you feel. Make sure it's worded in a docile way. Be all emotional and let him get the impression that you're not still angry, but hurt. He'll be less likely to go on the defensive if he doesn't feel attacked. Ask him if he's cool with everything or not and tell him that you just want to make sure that your friendship is OK.
Who knows, you may even get an apology out of it. He probably does regret whatever happened and would just rather not talk about it. You giving him the chance to talk about it could help.
But this is with me only knowing your side of the story. I have no idea what really happened. Keep in mind that it could be that you DID act maliciously toward him without even realizing it. People don't often realize when they're in the wrong. It could be that you were just a total bitch to him and that he had good reason to be pissed at you, in which case you should just shut the fuck up and be glad he's forgiving.
That's something else to consider.... Even if he was in the wrong, if he believes that you were the one in the wrong and that you were "against" him, the fact that he's put it aside and resumed his friendship with you shows that he cares and that he's willing to overlook how you've wronged him for the sake of your friendship.
OR, it could just be that it was never a big deal in the first place and that you're just blowing this out of proportion. Maybe he never really cared that much about the fight to begin with.
Again, without knowing his side, I'm kinda limited on the advice I can give. Maybe something in this has helped you or given you an idea of how to act. I'd suggest going with the e-mail and gently talking about it again to sort things out. Good luck with it.