I reunited with my best friend from my youth about 8 months ago. We hadn't seen each other in a million years. He was almost two years sober when we got together. Things were great at first. I was so happy to have him in my life again. I thought we were meant to be together. There were some red flags. Then he relapsed. Then he relapsed again and said a lot of hurtful things. I'm on week two of our break up. It's been heartbreak. I wasn't waiting for the horror, but it happened anyway. I thought since he had almost two years of sobriety and sounded so confident, that he would be ok.
I hope your friend stays sober. I really do. It's smart of you to keep your eyes open, though, like you are and to read and read the threads in this forum.