DowntonTrout, your mums situation at the moment is similar to my grans who died earlier this year. She had dementia and after a fall, it all got worse. Soon after my grandfather died and that seemed to really make her worse. Maa stopped eating for a few weeks before she passed away. Before that she was eating very little. One boiled egg in the morning that my mum would feed her and after that nothing. She had some energy drinks that we'd talk her into sipping but she'd get agitated if we tried too hard. In the end, it was just water and then not even that.
Nearer to the end, Maa began asking for her parents who had died years ago. It was heartbreaking to see her in such a state. She hardly recognised any of us but did rember when she was reminded. Surprisingly, she recognised my husband better than she recognised me or any of her own children.
In the end, she stopped talking and would just sleep all day. We were quite worried about how much she used to sleep but realised only afterwards that it was part if the process of her body shutting down. We tried giving her medication or water ourselves but despite being such a weakling she'd push us away with so much force and determination. A stubborn woman right until the end we'd joke. But yes, she did not like us forcing her at all. She won that one too.
She died very peacefully, with all of us around her. All her grandchildren and her children. She stayed at home with us and we had kept a vigil at her bedside for months.
Looking back, there's nothing that we could have done differently for her. I can understand your frustration and its only out of love for your mum that you're feeling this way but my gran was at home with us and she was still the same. There was someone with her at all times. At least four or five people in the house all there to make things comfortable for her and tend to her needs but she had no needs; she just wanted rest.
Having been through something similar I can only offer my thoughts and prayers and empathy. My advice is to spend as much time with her as possible and to sit with her holding her hand, telling her anything you want her to hear. She'll take comfort from your presence and if she can't see you, your hand in hers all day with let her know you're there. This is what we did with my Maa. That we had time to sit with her and care for her at the end made the grieving process so much easier.
I know you write your siblings are not there, but you're the lucky one. You're spending time with her, caring for her, being the one familiar presence around her. In the years to come you'll treasure these moments and will be glad it was you sitting there with her.
Lots of love and hugs to you.