When I was an early teen, my mom sat me down and had that talk with me. She hadn't quit (yet), and I was actually pretty angry as it seemed to me that she was making excuses, telling me about all her reasons for becoming an alcoholic, excuses. Then she drank for a few more years. I didn't CARE about the details, it was too much information that she (in my opinion) had no business laying on me. I still think back to that talk and feel uncomfortable. Then, a few years later she (and my dad) quit drinking and never looked back. THAT was the important stuff, I don't want to know why, how or anything, I just wanted a sober mom who was dependable, trustworthy and present.
That being said, I know there are a few books for kids about alcoholism, but really until you have some significant sober time I think it's unfair to present hope and a finality to it that might not quite be real yet.