Janet,
Actually, X's mother was a very sweet, kind lady. The problem was, by her own admission, she was not able to be there in X's life or her sibling's when they were in their teens (same mistake I made emotionally with my now N daughter). X raised herself and her sibling for the most part, and so, never really got to know what being a "child" was about. X learned that it was her job to have all the answers, fix things and people, and that she was NOBODY if she could not fulfil this role.
Janet: I don't know if my NMum had ALWAYS thought like this, but it certainly seemed as if, in her eyes, anyway, we had pre-destined roles, and we HAD to fulfil those, or fail.
Perhaps she had decided *I* would be the Golden Child, but I had refused that role, so she transferred it to my sister, who was less 'rebellious'?
My guess is that, yes, your Nmum had always thought to have you so you could be with her forever. How do I guess this? Cause children who grow up in dysfunctional families, tend to want someone "to love forever." I WAS THIS CHILD AND THAT WAS MY FANTASY. It was why I got pregnant at 18 by a boyfriend whom I dreamed would wisk me off and marry me and I'd live "happily ever after" with this blissful little baby that loved me and lived with me forever in the palace of my mind.
Now, hopefully, normal-minded people will WAKE UP and realize that this was JUST A FANTASY, like I had to. Apparently, your own Nmum did not have a ability to separate fantasy from truth at the time and still doesn't.
In the case with X in my life, there was one daughter who did not fulfill the role of mirror. X had nothing but complaints about how she wouldn't do "fun" things with her, etc. So, X found another "daughter" to bring into the situation, a girl she picked "off the street" so to speak, that she could basically turn into her cupie doll, dress up, re-form, etc and later, when the girl tried to individuate, X threw up the usual "after ALL WE DID FOR YOU! WE MADE YOU WHO YOU ARE" thingy at her. The girl decided she didn't want to be part of X's fantasy anymore, partly because of how she was being treated behind closed doors, although X would never admit to that to me or anyone else.
After X's pseudo-child left, guess who was NEXT in line to play the role..................yours truly, and, sad or maybe glad to say, I FAILED MISERABLY AT IT! I couldn't second-guess what X wanted, like pseudo-d did, I couldn't be thankful enough to X and her spouse, like pseudo was, I couldn't read X's mind or do what pseudo used to do apparently without flaw...therefore, DEVALUE, DISCARD, REPLACE! and out the door I went with a "consolation prize' of a sort.
That's how it works. It's insane, but it's what they do, because it's all they know to do.