There is no winning with an addict. My addict was a no call no show 3 weeks in a row and then gets in touch with me to see his son and says I'm holding him back from his son. There is no win. Save your energy.
I have set boundaries. You count too. I have decided not to do holidays with his family anymore. Too emotional. I had to make me healthy too.
Yes, be nice. But let go. That's the hard part. Anger leads to unhappinesses. Kindness leads to happiness. You can be kind to him, but you don't have to take his crap. You will never get what you need from him because he is an addict. If I ever have to deal with my addict, it is via email and text. I keep it very professional and positive, but to the point and one to 2 sentences. No emotion. Sometimes I dream of telling him off. Usually he reacts to anything I say like a jerk. In fact no matter how I word it, I get anger back. And I ignore. I don't engage. So, work on letting go and surround yourself with happy. You don't need to put yourself in an awkward and uncomfortable position anymore. It is done.