Does she have a diagnosis of dementia? If so, this behavior is more common. I would try a few things. First, fortify her food as much as you can, (adding plain protein mix to foods or giving supplement drinks like Ensure). Then, only offer small portions of food each meal and serve it on a bright red plate. Sometimes, the amount of food can be overwhelming, making your mom not want to eat any of it. The color red can stimulate appetite. You might also try giving small snacks throughout the day that will help boost calories without making her feel like she is eating a full meal. Hope this helps!
My mother has dementia and has been in-home hospice care at my home. She almost end up taking food my mouth two days ago. She was coughing from 5 am to 9 am this morning and coudln't get it out or swallow it. Administering 0.25 ml morphine didn't do much. Hospice care does not give IV for dehydration.
I'm so sorry to hear about your mom. End-stage dementia is extremely tough. It sounds like your mom's body may be in the process of shutting down and her body does not desire any food or liquid anymore. Her body is also having a hard time trying to figure out what to do with liquid since her brain may no longer know how to swallow. I wish I could give you better advice, but I think at this point, just being there with her is the best thing you can do. Prayers to you 🙏