I utterly feel your pain and can tell you it's her, not you. I have a mother who sounds similar. When I was a child myself, siblings and dad were all abused by her. When I grew up she behaved ok to me so I kind of 'forgot' how bad she had been (more fool me). I think during this period she continued to treat my dad like utter shite (he was her kicking boy) as all her kids were away from home and thus could not be touched to the same extent less anyone outside family saw her behaviour.
I foolishly tried to look after her in old age and as my dad had died she reverted back to me being the kicking boy and abusing me. I did it for 4 years before she went into a care home where she currently is.
During those 4 years I was threatened, shamed, guilted, humiliated. She told countless lies to people about me. During the time my physical and mental health plummented to the worse state I have been in ever. Like your mum she had no qualms whatsoever about kicking up holly hell if she did not get her own way. (phoning police telling lies about she had been abandoned, screaming at me when I had bad covid in 2020 because I wasn't well enough to do what she wanted, told me repeatly that I was useless, no wonder my dad hated me, no wonder my siblings hated me, my ex boyfriend was right to have dumped me.
All the bad stuff she used to do as a child came back to me and it was just horrifying.
There is a sort of thought process in society that old ladies are sweet old things that are vunerable and helpless. It seems unacceptable that some are actually monsters. They always were monsters, they are just old now too.
If you are the big, strong, younger daughter it must be your fault because your mum is now shorter, thinner, frailer and older.
I will just give you some examples of behaviour from her as I am pretty sure she is very similar to your mum.
When I was a kid it was my job to cheer her up, listen to all her problems and calm her down. I used to spend my pocket money when about age 5 to buy her things she used to hint she wanted to make her happy
She used to tell me and my brother my dad was kicking us out and we were going to have to sleep on the streets and it would be terrifying. Me and my little brother would be terrified and would cry and beg my dad not to. My dad had never said any such things but my mum was using us to win an arguement. The fact she was traumitising her kids was of no consequence.
When I was 19 I moved down south to live with long term boyfriend who had got fab new job. Within 3 weeks my dad phoned me to tell me I had to come home to 'fix my mum' as she was depressed. I went running.
She told me when I was a child my dad wanted to have me aborted.
She used to tell tales to visitors to get a laugh which basically involved mocking and humiliating me.
She used to say when we were kids she was so poor she had holes in her knickers and used to worry about being in an accident. However she didn't mind as she wanted to be a stay at home mum with us. As a child that made her a hero in my eyes, as an adult I can see she wanted us to feel grateful for her sacrafice and guilty of the burden we were.
She played all her kids off against each other so we have no relationship.
I got told on a weekly basis what a burden I was
As an adult she tells anyone that will listen that I have mental health problems whenever I try to stand up for myself against her. (I do have mental health problems but because of the treatment not because of the standing up to her)
Nothing is more awful than somebody who kicks you and treats you like utter shit and tells everyone else lies about you.
My mums GP had an awful time with her and I was sort of glad that a professional person was 'seeing' her. Her GP told me she likely had a personality disorder. She tells lies constantly, creates drama to get attention and has zero sympathy for anyone else (though she will pretend she does).
My mum went into a care home because of fraility and cognitive impairment. To this day I still think a big part of her cognitive impairment is actually just her being her usual self. She got credit for 'oh she called you a useless cunt' it because she has cognitive impairment. It may have been or it may not have been as she always called me and my dad these kind of names in private so when she started doing it in public was it dementia or just her forgetting to do it only in private.
You will never win with her. If you are a perfect outstanding daughter for 100 days but on day 101 you fall sick, your name will be mud, you will be slagged off to everyone until you drag yourself off your deathbed to do her bidding.
Everyone who has a normal mother cannot understand. They say cut her off. However when you have been brainwashed as a child to do her bidding it is not so easy. Your self esteem has been broken, you are probably suffering CPTSD.
I'll be safe when she is dead and not before that. Although she did tell me when she died she would come back and haunt me so not to think i was getting away from her.
By the time my mum went into care home I was truly contemplating suicide as a way out to get away from her. Since she went into care home I have not returned any of their calls or visited her once. I will have the joy of selling her house/clearing it but I don't mind doing that as it does not involve seeing her. Not looking forward to it or anything but doable. However hell will freeze over before I see her again or spend one more minute in her company.
I know for a fact she will be telling everyone at the care home what a shit useless daughter I am and how she was such an amazing mum and that she can't understand it.
Monsters wear many faces. Sometimes they have white hair, frail bodies and abuse their children.
My advice - tell carehome you will speak to staff so your mum can tell them what she wants and they can tell you so you have no direct contact with her. You can pick up things and drop things off but to care home staff only.
It's quick a shock when you realise the biggest 'enemy' you ever had was the person who was supposed to protect you and love you.