Husband's neurologist suggested stopping Memantine and Donepezil. He is in Stage 6. I'm afraid to have him stop. Anyone stop meds?

These are both medications for Dementia. At stage 6 they probably are not doing him any good.

My DH aunt (97) stopped one then the other a couple of years ago. Turns out the Donepezil caused a slow pulse. We had been treating the slow pulse for years by holding one of her BP meds and increasing another on the days it was too low. Once the Donepezil was stopped, her pulse stayed steady in a normal range.
It was difficult (for me) to tell if the meds helped. Her geriatric primary felt it slowed her dementia. She is bedfast for several years, totally incontinent. This all before we stopped the meds. She goes for great lengths of time not talking, just one or two words and then she starts talking as if she never stopped. It is a baffling disease.

What is the doctor seeing that he/she has described as worrisome to him/her? Or is this simply because the medication is not having the desired effect? People look on meds as always a good idea, and as benign, but they are not. They are very hard for the kidneys to deal with for starters.
If the doctor has reasons for withdrawing these meds ask what they are.