I guess for myself I need to clarify and say this. Recovery is a long road. Not one that happens overnight. However, I do not believe if you are blaming everyone but yourself you can even begin. Just my opinion.
As far as saying someone is a good or a bad parent, my comment to this would be that I don't think it's even possible to be a good parent if you have not even begun recovery. Also my opinion.
In my world, you have kids and they become #1. Their needs before yours. You had them, so you are responsible for them, and to what is best for them. I will also clarify one more thing. I am sure the children are taken care of. I am more talking about their emotional well being. If she is running them down, etc, that is not taking care of their, or her, emotions.
I am sorry if any of this is harsh or hurtful, it's not meant to be, as I know it's painful to watch those you care about go down the rabbit hole of addiction.
I truly hope that she gets the help she needs so she can absolutely become the person she needs to be, the children need her to be, and you need her to be.