good morning yooper01,
I am sorry for what brings you here, but glad you have found this wonderful site. It sounds like you have been through the ringer, and have been hurt so much by the addictions of your loved ones.
First and foremost, you know that all you can do is what feels right for you. I hope that you take care of yourself, and that you realize that what other people do is out of your control. I know it's hard, but try not worry about what your son's friends or other family members do. You can only control your own actions, and take one day at a time.
There is a great post here in this same forum...The Battle Isn't Yours to Fight. Please read it if you haven't already. I read it a lot, so that I am reminded. Our sons are grown, and as awful as it is to accept, their choices will result in a life of their own choosing, and we have to just step aside and hold on to whatever happiness we can find in our own day to day lives. It's hard, but it's all we can do.
Stay here, keep reading and posting...there is support here, and you have a lot of experience that you can share as well. May help others, and in the process help yourself too.