What does it mean if a guy isn't good with people and is unsociable and is isolated And unfriendly?

That he’d make a perfect SW user.

It might mean he's been terribly hurt and he's healing. Or else he simply loves to be alone and there's nothing wrong with that.

It means it probably wants to be left alone .. he got so used to being rejected or alienated from people he just stopped caring

He is most probably done with being friendly. I mean the guy is highly disappointed with so many things.

Maybe he just prefers his own company, or he's sick of other people letting him down.

Probably sick of people.

It doesn't "mean" anything. He could be neurodivergent, if that's what you're getting at.

It could be a mental condition or a result of trauma. They could also be on the spectrum.