I don't know if you're in counseling, but I would definitely get some counseling for yourself.
You can't help someone who doesn't want to be helped.
And this guilt of yours is not healthy for you or your kids.
When you get the help you need, you may be able to help your mother, and be healthier for your family.
I empathize with you. My father is an alcoholic. He refuses to get help. It seems as though he has gotten worse since my parents bought a new home. I don't know what to do either. But I leave it to my mother.
I stopped feeling guilty about it as a teenager. Every time I tried to speak up, it only made things worse between he n I. And being the only child out of the four that ever spoke up, it wasn't easy. I realized I had to stop trying to get him help and focus on myself.
My mother is a recovering alcoholic. She quit after finding God. I am so thankful for that. I can only hope that she will guide him to recovery. But again, you can't help those who don't want it. And he's made it clear that he isn't ready for recovery.
Just take care of yourself and your family. That is my best advice.
I'll be praying for you, your family, and your mother.
Best of luck to you. God be with you.
Edit:
Sorry. Just reread your post and realized you said you had a counselor. Sometimes it's hard to remember everything you read when responding.
I hope you are still getting help and that you have a good counselor that can help guide you away from your guilt.