I grew up with an alcoholic mother
You are doing the right thing to protect your children from that now that you know.
Don't let her talk you around or minimize.
What she did could have killed them and herself.
That's not a rational mind talking--that's an addict.
She may think she means what she says, but I'm an alcoholic too
and I can tell you that unless she walks the walk
don't believe a word she says or promises.
Actions over time are the only thing to believe.
Get temporary custody and show her by your actions you mean this.
It is hard, but may be the best thing for everyone, including her.