(((Imallright))) - so sorry about your friend. I can't really tell you why some people keep drinking, others find recovery. Alcohol wasn't my thing, crack was. I found recovery, my exbf did not and died a few years after we split up. My first exbf is still drinking, 30 years later, as far as I know.
Hugs and prayers to you, him, and all who love him,
Amy