I can relate to some of what you wrote. I don't understand my son's alcoholism. I know we gave him a wonderful life full of love. He, too, can be very selfish and has caused those of us that love him immeasurable pain at times. And, there are times I am very angry at him, but mostly I just feel sorry for him and feel sadness at what his life could have/should have been.
I hurt less when I quit taking it so personally. Its not really about me and what I've done or how I've treated him. There is something wrong with him ... I don't believe he would choose to live this life.
I'm sorry you are hurting. I've had a pretty rough week myself.
edited to say: Don't you have a pretty strong history of alcoholism in your family? Your grandson probably just got dealt an unlucky genetic hand for addiction.