Hi Mandjas,
I am so sorry you are going through this with your Mom. It sounds like you have been thru the ringer! I was very glad to get to the end of your post and see that nothing happened to your little boy. I believe that you are doing the right thing. What we learn about alcoholism in 12-Step programs is that we did not cause it, we cannot control it, and we cannot cure it. So, while in her mind you may have given her an excuse to continue drinking, in truth, you have not.
I hope that you will give Al-Anon a try.
Best wishes.