I agree - she is old enough to understand - if you are able to sit down with her and explain it to her.
Documenting it all is definitely the best to do - I'm not so sure you or your children having contact with him is a good idea - I can't imagine what it's doing to your health!
Since being away from the alcoholic in my life and surrounding myself with normal, sane and sensible people who care for me - life has been so much better. Sorry, you might not want to hear this - but my move would be to get away from this man before he drives you all crazy.....
