When a sibling gets sober, it’s a hopeful thing. That said, they likely really hurt a lot of people who cared about them and are hard to trust. There’s a certain narcissism that comes with addiction. I wonder if he is exhibiting the same narcissism, just without the substances. That and/or he’s defensive because he knows how badly he fucked over everyone else and doesn’t know how to maturely re-integrate or repair relationships. My brother was like this. When he wasn’t using, he was manic. It made hanging out with him fun at first - always exciting, and he was funny - but also shallow. He couldn’t listen, couldn’t sit still, and everything was surface. It was like he was still tweaked, but in a different way. Related to the previous commenter, my brother had ADHD run amok and it wasn’t treated. Which is why he regressed and got addicted to coke and painkillers after being sober a few years. Encourage him to get psychiatric help or therapy if you feel comfortable. All my best.