I'm not saying you are or anything, but definitely don't feel at all responsible for influencing his decision from that chat. Obviously he was in a bad place, and doesn't really sound like he had any support system in place. Just fucking sucks that all his family failed him and yeah, someone should have made a report 100 percent. CPS isn't great, but it would have been something and he probably would have ended up better off.
There's not much you could have done though, man. When people are that deep in a well of despair they never think to ask for help because they feel they don't deserve it. You talking about that made me think of my buddy who hung himself a few years ago. He kind of just went unhinged for the months leading up to it, where I avoided interacting with him anymore because he just seemed so off. Randomly taking shots at mutual friends publicly out of the blue saying nasty shit. He also started posting a lot on social media about being lonely in awkward ways and many people made attempts to try to connect but he just blew it off or it never filled that gaping hole that he had I guess. Just hard to get people to crawl out of that mental space when they're spiraling.
RE: I was a musician. I was never a good one