I have a friend who's an addict and he's becoming impossible to talk to. Not about drugs, just about anything. He doesn't want any help, and he starts to live in his own reality. When we meet in a group of friends he doesn't listen to anyone. He can talk non-stop for hours until everybody around is tired from his gibberish. But he doesn't listen to anyone in a sense that feels very selfish. For example, when someone is telling an interesting story, he won't listen and he would make dumb offending jokes.

It feels like drugs made him dumb and also he is living in some kind of parallel reality. It's becoming harder and harder to connect.

Also, in his reality it's perfectly ok to consume drugs, he's also constantly offering to share the experience with all people he meets.

It's sad situation and looks desperate because he's aggressively against any help, he consider himself better than others because of the drugs (he is sure they allow him to "see" more than we see), and he doesn't listen to anyone.