Hello hummingbird, I hope you know that you are always welcome here. Welcome to talk about this all you want or need. I completely understand the need to 'get it out'. Sometimes my late husband and I talked about his son's drinking so much that we referred to it as "the topic". It's good to have another way to release some of the sorrow, anxiety, and grief.
My late husband would take calls from his son even when he'd been drinking, too. If I had been working in another part of the house, I would sometimes return to the living room and find him on the phone just saying "Oh?" and "Mmhmm..." and I he would look up at me signalling that it was his son.
Some may not understand and completely disagree, but my husband felt that it was his one way to at least keep a line of communication open with his son.
I hope and pray that your son will find the strength to push through this and really get some help for himself! I hope that you will find your peace and joy. You are all in my prayers.