Anyone have suggestions for elderly parent who refuses to take meds?

I am the primary caretaker for my 99-year-old mother whose cognitive abilities have been deteriorating more in the past few months. She does not have dementia in the sense that she recognizes everyone/her daily life, history etc. but her short-term memory is very poor and she asks the same questions (eg: What time is it? What day is it? What are you doing today? Did you talk to [sibling] today?) all day long. I manage everything in her life - finances, healthcare, meals, maintenance, transit, clothing etc. - and medications. I order them, organize them and give them to her. About a month ago, she started debating with me about having taken them, and then refusing to take them. This has now become a regular thing. My brother suggested I have her sign her name in the morning and evening when she takes them so she has some agency. That worked for a couple of weeks and this evening she signed her name, I handed her the pills, and she looked right at me and said, “You already gave those to me, I’m not taking them.” I showed her the paper with her signature - made no difference. I have all the pills in view and they are marked Monday-Sunday and times of day. The morning pills were gone and the evening pills were in the cup I handed her. It made no difference - she refused. Suggestions?