Mum refusing to eat or drink. Any advice?

My 81 year old mum is in a nursing home. She has dementia and when dad was alive suffered from delusional paranoia jealousy type. She was adamant that dad was having an affair and am sure she drove him to an early grave. We moved her into a nursing home 8 months after dad died as she couldn’t look after herself and constant falls on top of being a diabetic. She took about 12 months to settle into the home and had her favourite staff members who all look after her very well. Three weeks ago she started to not eat as much and then within a week refused food and only takes sips of various drinks. Also very lethargic all she wants to do is sleep. The doctors thought she had a UTI and antibiotics did not improve her and also put her on a drip which was removed after three days as fluid was building on her lungs. She is pretty much bed bound and the staff do put her in her wheelchair as do the family to take her out but she just falls asleep and begs to go back to bed.

Doctors say her dementia has triggered something and to prepare for end of life.

I am interested if anyone in this forum has experienced anything similar. I have been visiting her three times a day worried that she may pass away on her own. Work has been good allowing me to work from home but it’s been three weeks now. Her obs have been stable and I am feeling torn about going back to work or staying at home.

Any advice would be most welcome!