I am not so sure there is any good time to bring it separation and in-house separation. I will say in-house separation is the absolute worst.
I just told ex-alcoholic that I could either have him served which would cost extra money or he could sign the waiver. He signed and we did in-house separation until the day of the divorce. It was not a pleasant time, but there is life on the other side.
As for expectations, lots here will tell you to not expect in a divorce what you did not get in the marriage.
I am luckier than most as I do not have to worry about ex's parenting skills or lack there of. We live in different states now so he does not factor in to our daily living.
If your H is still drinking, I would not expect anything of him parenting. Sorry, but that is what I learned.
The other thing I learned with an alcoholic during in house separation are "there are no rules".
(((She-Ra))) and welcome!Life is meant to be lived, not numbed!
In his quest for freedom, he set me free!