Also due to the
devaluing Extraverted ethics in a EIE is often oriented in a negative fashion to make others uncomfortable, to shake them out of their comfort zone. Don't think that people merely use their ego to make others feel better or work better, often the capacity of the ego is used to destroy, to hurt, and to damage others.
Her mom knows very well that she is crossing boundaries, but there is a compulsion to do it, because she wants that to be notices, she wants to be noticed.
My mom is EIE as well, and thru my life
I've learned how to deal with her, and it's not about being nice. What I have to do is this. I have to tell her what she's saying is stupid/wrong, I'm right and she needs to listen to me and do what I advise. You would think this is abusive, but it's amazingly functional in dealing with her. I love her, but this is the only way I've learned how to deal with her, by imposing my will on her thru aggression and making very clear what my opinion is to her and how everything works. This is what her dual(LSI) would do. Luckily, as the benefactor, these are two of my mental functions as well as contact functions. I don't like to do this, but I can readily do it in order to emulate the behavior of her dual.