First, how old is DD?
IME, you need a legal parenting plan, one devised by a lawyer. You can't force someone into being honest or showing up on time, so feel free to relieve yourself of the responsibility to do so.
In the meantime you have to come up with a way to care for your children without his help -- an active alcoholic is not an appropriate caretaker for any child. If I were you, my first step would be to call the school and find out what kind of after school stuff they have. Then I would blast Facebook and see if any of your friends can help watch your daughter in a pinch and/or during the afternoons after school. I've bartered for childcare, like, if you help with this, I'll watch your kids on the weekend for a date night, or whatever. I've had to get pretty crafty. I have some family help, but recently I've had to take on a second job so I can make ends meet so I don't have to rely on my dysfunctional family or my dysfunctional AH. It sounds overwhelming, but with a good attitude and some determination, this new normal will work our better for you and DD.