I'm sorry for what you are going through. A month and a half ago my dad passed on (he was 85 as well).
We lived together for the last 7 years. I'm thankful for time that we had together and that he was blessed to have his mind.
We were never JWs.
I am thankful that I was able to share about who Christ is, and what Christ did with my dad. Just as we had in the past we said goodby, -only this time it will be a little longer until we are reuinted.
My grandmother had alzheimers before she died. I think that they can know whats going on more than we realize.
you are in my prayers.