It is awful, and I would have said impossible until I recently encountered DD's boyfriend's mother, who seems very much like this to me.
She wants to control and parent two twenty somethings as if they are toddlers and dislikes me because I don't share her views or approach. Apparently that makes me an unsupportive mother and she will have to step in!! Yes, she did try saying that directly to me and I pulled her up very sharply on it! I refuse to see her now and have banned her from my house. Her number is also blocked on my phone and it will stay that way.
Everything in their house revolves around her with a "yes Jane, no Jane, three bags full Jane" so she got a shock when I refused to dance to her tune and told her to bugger off. I am now persona non grata to her, which suits me just fine.
I could write about her antics all evening (many incidents, and she is unbelievably awful) but I will leave it there for now. I don't want to misuse the terminology, but she is so self centered and her behaviour and reactions seem so spiteful and extreme that I actually wonder if she is a narcissist. There's certainly nothing about her that seems normal to me.
I feel sorry for her son. He gets very upset about it all and finds her excruciatingly embarrassing.