My explanations probably sound like refreshments for a pity party. I think it's time to close this too long post.
To answer the medication part... First, I have discussed this regularly for 4+ years with my doctor, and he is has no argument with my thinking. As to the MRI, and current medications... I don't want to go through tests and reports and being part of a study. Hopefully some of the newer studies will shed more light for a solution for others.
https://www.npr.org/sections/health-shots/2019/07/04/738478841/new-markers-for-alzheimers-disease-could-aid-diagnosis-and-speed-up-drug-develop
As a little background... my mom died in 1984 on moving into stage 7 of Alzheimer's. She was 74 and the final months were fortunately not traumatic. My dad died of cancer at age 56, and my mother remarried, happily, two years later. As far as I know, no other relatives with AZ.
So, on to today and the future (at least the future for jeanie and me).
No secrets in our family. The kids all know what's happening (after their several years of denial), and jeanie and I are on the same track... understanding that at our age each extra day is important...
The good part is that this gives us a head start on planning. We are prepared legally, with wills and POA's. the money part, while not great sees enough for a total of 10 years of nursing home/and or "Memory Lane" as it's called in our CCRC. An old LTC policy provides $36,000/ yr. help with this... Policy for each one of us.
We have regular wide open meetings with our four kids and their families, so they are prepared for whatever happens. Money, housing, medical care and our current lifestyle and budget are all part of this.
For jeanie and Me...? We still do the morning two minute hug, that does wonders for our outlook. No sadness... every day a gift.