I had one of my best lifelong friends die of this last year. It is still very sad for me.
We tried intervention over a decade before. He was forced to go to AA for awhile under threat of losing his job. None of it worked. He was too deeply into the pattern.
Even among his best friends who know everything we debate the cause – genetic, environmental, personality, some event…
Brian, I would just say enjoy your time with your friend. Go do things. Don’t try to fix it. I don’t think you can.
My friend was an asset to the planet – a popular teacher. He did not make it to 50.