Dearest Jezzer this is so terribly hard for you and I am very, very sorry.
With my mother, I found, though on just one occasion, that I was with her when she was dozing but aware of my presence. The sun was pouring into her room. There was an extraordinary sense of peace.
It was as though our two spirits were there, communicating silently, in that shared space. Oddly, this happened when I stopped trying to communicate in spoken words.
If you are finding this stage so stressful, as of course it is, no question - then I wonder whether experimenting with just being there beside her, and using the time to find a moment of calmness for yourself, just grounding yourself and concentrating on your breathing, might be a pathway to silent communication with your dear mother? She may then, in that silence, be able to respond similarly, and share her love freely and abundantly with you.
I don’t know! But worth a try?