Yes, I’ve been married to a “functioning” alcoholic-it’s a grim way to live, I’m really sorry you are finding yourself there too. Please don’t let the “functioning” bit fool you. He is an alcoholic, end of. Unfortunately, unless he stops first (less likely), he won’t always function (much more likely that he’ll carry on to this point). The functioning tends to deteriorate as the addiction slides abs alcoholism is, I’m afraid, is a progressive problem.
I totally recognise the checking out of family life and responsibilities. That’s definitely part of the pattern and it’s really hard. I hope you have lots of support around you and if you haven’t already, I really urge you to be open about it with people close to you.
You say the staying in bed may be caused by depression. Of course, it might well be, but alcoholism causes depression and it’s more likely he’s in bed because of the effects of the drinking.
The downturn in his sex drive is likely fuelled by the booze too.
I know you probably don’t want to hear this, I understand how hard it is to accept (and how much more difficult it makes your life), but you really need to be extremely careful about letting him have sole care of your dd. At that level of drinking, he is likely to be often over the limit the next day.
I eventually left my exh to protect my children from the effects of an alcoholic father and to protect my own sanity. It certainly hasn’t been easy BUT, as others have said, the relief of no longer dealing with that is immense.
Look after yourself and your ex, whatever you decide.