Well, to me it is already, too bad. Bad enough.
The kids are in trouble... and everything is affecting them, and their ability to do well.... in all aspects.
Bottom line is, they are REALLY suffering and cannot cope.
Has the Mom always had a presence in the kids lives?
Or only now, recently?
It is not affecting them well.
Its good you got counseling. It can take a long time.... consistently. Don't expect it to change right away. Do the counseling regularly...
If the Mom, is impacting them so badly... do you HAVE to have her presence in their lives?
The Mom is the way she is... you can't change her.... you didn't mention it, but she seems to be a bad influence???? Or at least unstable???? She does not seem 'willing' to be a part of their lives?
And if she is... well, how is their relationship going to be?
You can't 'force' the Mom to have a relationship with the kids or to be a REGULAR part of their lives... if she does not want to.
You/Hubby have been raising the kids full-time as you said... so He has full custody? I would leave it that way.....
The courts, have the say.
Do you have an Attorney?
Bottom line is the childrens well being... with the Mom or not.
If the Mom is a bad influence... why have her in their lives... AND, what do the children feel? Do THEY want their Mom around???? It seems to create a lot of problems in them....
Toxic people.... will be a detriment... to adults and children. But children have no control over it. And the Mom, will undoubtedly be much trouble... to you/Hubby as well.
DOCUMENT everything....