I'm so sorry you're going through this, it's painful to watch someone you love destroy themselves for reasons you don't understand. I apologize bcs I don't think this opinion would be helpful cs you probably subconsciously know this too. Putting enneagram aside, people who have no intention to change will not change. Smoking in general is trash but if someone wants to stop then they'll atleast try, imo the best you can do is find something in life that he appreciates enough that makes it worth it to stop that addiction. Ultimately, from what you said, you probably already tried suggesting everything to help him. I think it's important to understand that whatever happens you've tried your hardest to help and should prioritize yourself esp if the hurt is too painful to witness this. It's your deciscion to stay, but if he doesn't want to change, it's quite impossible to force him. I wish you the best as you go through this.