Dean - I am so, so sorry. Please know that even as a total stranger half way around the world my thoughts are with you.
I'm not going to tell you what to do or how to act. This is a deeply sad and personal time for you.
I'm not going to pretend to relate to such an event. I just wanted to share something about me, as it's what I do know. I think you and I are about the same age, and like you my mom is my best friend. About 4 years ago we started seeing signs of memory loss and as this continued it got increasingly worrisome. Regardless I always held out some hope it was just "senior aging" as I was sure she was simply too young (around 67 at the time of initial symptoms?). Last holiday season I went home and came to the stark, brutal realization that my mom was absolutely, without question in the moderate stages of Alzheimer's. The smartest, most amazing person I know had lost her ability cook meals, operate her phone, recall the names of her grandchildren. She know longer new my birthday... such a small trivial item, but something that had a profound impact on me. Alzheimer's is an incurable disease, and it's much more likely than not I will lose my best friend to a long, difficult, painful journey where her body outlasts her mind. It's a disease called "The Long Goodbye" for good reason.
I went into a grieving process of my own, which is common for family members of those faced with this. And I did all I know how to do - I drank. A lot. I clearly increased my already high intake...
It took an already painful event and simply surrounded it with an additional layer of... confusion? Like, I felt the pain, but had no ability to actually process it. The alcohol didn't even really sedate me, it just sort of paralyzed me in this haze of sadness.
Anyway, this is your experience and your pain and your life. But just from my experience, alcohol restricted me from doing the one and only thing you can do in such an event which is to feel it and eventually move forward with some clarity.