Reddit mentions of How Al-Anon Works

You're not going to fully understand what he's been through or what recovery is like. That experience belongs solely to the alcoholic his or herself. And what you'll find if you look more into these books you mention is that the "target" audience extends way beyond people with active alcoholics/addicts in their lives...It also applies to people who, at some point in their lives, have been involved or affected by another person's drinking either active or recovered. The alcoholic's...alcoholicness doesn't just go away once they start recovery. It continues to manifest in both of your lives in ways of which you are not aware yet.

Lastly, I know this isn't what you necessarily want to hear, but the best possible way to "understand" every thing is by focusing on understanding yourself. You can be as supportive as possible by taking care of yourself first. It seems counterintuitive, but it works.

Go to an Al Anon meeting. Pick up a copy of How Al anon works either there or online

This book is a great way to start. Good luck!