'Awww big hugs to you, it's so sad at the end, you want them to get better but at some point you accept this is natural, they have withdrawn, their body is saying enough now.
Have you contacted a local hospice? My father's care home called in the palliative care team in his last 48 hours. They had drugs to hand to clear his chest secretions when he could no longer cough, and midazolam, an extra pain killer for when he showed signs of more pain than his morphine patch could ease.
I often thought in that last week that dying is not a spectator sport. There were several times when I had to walk away as I couldn't bear to see him for very long like that, every fibre of my being just wanted to help him. Reading the Alzheimers fact sheet on end stage dementia reassured me enormously, this was normal, it is part of life's rich tapestry, the last patch on the story. Be strong and be there when you feel strong enough, with love and gentle touches x