Thank you for sharing your story. It has to be hard to type it out and it is hard to face. It sounds like he is in quite a bit of denial about his alcoholism, or at least he is making you think he is. I understand, I know what it is like to walk on eggshells and be upset b/c they are acting like a nut and playing w/the kids when they have had a couple and be all upset and grouchy the next. What I have found out recently is just how much that behavior affects the kids. I encourage you to talk to the older ones and reach out and make sure they can open up to you about it.
Do you have an Alanon or better yet a Celebrate Recovery anywhere near you? You will find CR at churches, it is alot like Alanon and has helped me immensely. Many of them also have programs/childcare for children in all of your children's age ranges.
I wish I knew all the answers. All I can offer you is support, encouragement, and my prayers. I just signed up for therapy and think it is going to really help, it did even after one session. I know I can only change myself, so that is what I am working with.
God Bless!