Memory Loss

Both of my parents are suffering tremendous memory loss now.
My mother's short term is zero, and well, so is her long term.
My father's has diminished to perhaps a day.
I have to switch gears now with my father to the way I speak to my mother.
I never say "remember- such & such", because he doesn't, unless it is from the way past. I felt pretty bad yesterday when he said he needed to make 'preparations' and I was taken aback - He was actually surprised when I said he had paid for and signed papers for cremation.
 He has said he wanted this for 20 years! Now he acted like it was all new.
It was painful, but quickly forgotten.
My mother will have nothing to do with any conversation about it-- Never has.
The only difference is now the conversation goes the direction every conversation goes we have.
" I want to go back to Ohio".