Hello Naomi
I'm really sorry.
Yes, Alzheimer's does trash the lives of the sufferers, and also of anyone who is very close to them. There's no point in trying to hide that.
For all of us there are lots of lost futures, things that might have been. We all miss some beam of light that our loved one could uniquely bring to our lives.
Once the illness starts to take over, all we can do is our best to make things as comfortable as we can.
First important stage is to draw a line under our previous lives because it won't be the same again. Having done that, we have a choice. We can walk away, or we can hang on in there.
If we hang on in, then we need to establish a new relationship with the person. It will be different and, yes, you are correct that there are huge similarities between the needs of a child, and of a person with dementia. The key thing is that as your little girl has immense trust in you, so will your Mum [as she always has had, of course!].
It may be impossible to put aside those glimpses that provide a comparison between the Mum you see now, and the one you once knew. But she IS still in there. Believe that.
If your Mum would be best cared for in a home, then that is the important thing. Not your feelings or your ideas of what her feelings might be - that part of her is changed now.
Care homes often get a bad press. They are not all like that. This afternoon I was at the funeral of a man who was a younger person with Alzheimer's, and a resident at the same home as my wife is in. Some of the staff from the home, ones who cared for him, were there too, and they were crying. The staff get really attached to their residents. We all only knew him when he had dementia - but he was well worth the knowing, even then - perhaps especially then.
If you can, try mentally to step back from your Mum, then approach her again and begin to establish a new relationship with her as she is now.
I did that with my wife Jan, and I have been in awe of her strength in fighting her dementias. She has taught me tons. And frequently she is able to give me a flash of herself as she was, and it is so worth waiting for. That makes things better for me because I know that if I hadn't taken the time for her now, when she might otherwise be alone, she would have known it. So would I.
So look upon the time ahead as an opportunity to learn about another side to your Mum. As you do that you may feel less pain inside yourself as you become absorbed. Don't worry about her incontinence, feeding, and the other things that will change, because your Mum will probably accept that as quite natural now.
Oh, and do continue to take your little girl in to see her, so one day you can tell her she met a very fine lady who would have liked to have known her.
It IS hard. Best wishes.