I'm so sorry about your brother, Cindy. I have a strong history of alcoholism in my family, so I know how awful it is to see your daughter with the same demons in her life.
I think for many of us, finding some peace in our life comes after we have exhausted all other options and have been forced to make an impossible choice. It's like cognitive dissonance on steroids. There are no answers, there is no making sense of it, there is no right or wrong. We can't bargain with it or reason with it or wish it away.
Everything we've done or thought to do as parents no longer works, regardless of how hard we try or how many times we bang our heads against the problem. There is only the addict inside our precious child, and the addict wants to be fed at any cost.
For some of us, once we stopped enabling their addiction, our children were forced to confront the true cost of feeding their addict. They banged *THEIR* heads against the bars for awhile until they finally saw that there was no answer, and THEY chose to find their way out.
For others, our children unfortunately haven't found their way out yet.
For at least one of us, our child unfortunately lost the battle.
But for all of us, once we stopped enabling their addiction, WE felt better. We finally found some peace, by no longer looking for answers where there are none.
It's not an easy thing to do as a parent. It too reminds me of Alice in Wonderland; addiction is a rabbit hole where the things any "good" mother would do for her child only make things worse, and we are caught in the topsy-turvy of it all until we...just stop.
I hope you will reach out for other sources of support, such as Al-Anon, counseling, the books others have recommended, etc. You are not alone, not by a long stretch. I hope you will keep posting. We have a substance abuse area of the forum too, if that suits. Many of the parents on that area face similar issues.