Hard as you may find this, I do think it's essential that you DO interfere. Receiving help doesn't happen overnight so it's important you set the wheels in motion now to avoid some sort of catastrophe in six months' time. Contact Social Services. Contact your Mum's GP. Contact all the wonderful organisations which give advice on dementia. And don't give up until you're satisfied that there is enough care in place to keep your mother safe and nourished 24 hours a day.
I do speak from experience. The first signs of my beloved mother's Alzheimer's were apparent to me when she was in her early 70s. My father, bless him, and other members of the family were in denial. But I ignored this and went ahead with trying to make plans for the future. I am so glad I did, because demnentia/Alzheimer's does not, currently, get better. You have to face facts and make contingency plans.
I wish you luck, and hope you and your mother receive some much-needed support asap.
Severely depressed and confused
Russia was behind arson attacks targeting PM


She has Yoghurt Corners in the fridge and similarly packed rice puddings which I can suggest she has at different times. She is very ridged with her routines - at one point she always had Heinz Tomato soup for lunch - but now it is WFF for lunch and WFF for dinner.
I am only a little bit further away than you but we work on a drop and run system if necessary with frequent shorter visits. She is beginning to sleep a lot (I would be at 96 without all the other issues
)so me being there for long periods would mean her trying to stay awake and that would seem cruel in her case. No holidays for me either though for quite a few years but I am extremely lucky to have a very close family with my daughter nearby. I hope you have some help with your mum as it sounds as if you are doing a sterling job in caring in the way she wants and needs.