Welcome, I am sorry that you are in pain.
Your husband has possibly inherited the gene that predisposed him to addiction. This is a progressive disease that does not have any cure, he will be an addict all his life, it is just a matter of whether he is sober or not and working a strong lifelong recovery program.
With that said, he has now passed the predisposition gene onto his children. Now, that doesn't mean that they will become alcoholics or drug addicts. I am the child of an alcoholic, as is my brother and neither of us are addicts, although we both have either married or lived with addicts and have suffered from anxiety and a negative self image.
I can tell you from my own personal experience, I would have rather lived with one sober, loving parent in a reduced material enviorment rather than be exposed to the turmoil of addiction.
Your daughter is attempting to take on the responsibility of a parent, IMHO this is not a healthy situation for her. I've been there, done that, not good, I was forced to be an adult...way before my time...I had no childhood.
Take some time to read the stickeys at the top of this forum and the Family & Friends of Substance Abusers, lots of helpful information at your fingertips.
Have you considered going to Alanon meetings? Might be a good idea.
Keep posting, keep reading others posts and most important put those minor children first, you are their future.