I wouldn't tell my Mother or anything, but the last two years of her youngest great grandchildren's birthdays, she attended knowing full well what was going on.
My Grandmother was a dedicated Witness from 1972. She wasn't your MOST fanatical Witness, in the fact that when I found out about the false prophet I called her and she said "I can understand how you feel like that." Unfortunately, my Mother wasn't privy to most of the conversations that I held with my Grandmother. I knew, that in the late 90's she had begun to doubt the veracity of "The Truth." I was hoping that she would totally come out of it, but she never had a chance before she died.
When she was diagnosed with Alzheimer's in the mid 1990's, she had a lot of memory problems, of course. She had had a habit of picking up all the older sisters abd bringing them to the Kingdom Hall. From what my Grandfather said later, the brothers told her that she couldn't do it anymore because she was making all of the elderly sisters late for the meetings because of being lost. This hurt her very much, so my Grandfather says, and she quit going about 3 months before she died.
When she died, my Grandfather had a Witness f8uneral for her, because she was a Witness. My Grandfather went with her to the Kingdom Hall for 25 years, and he says they haven't been to visit him after her death. During the Witness funeral, it wasn't to celebrate my Grandmother, but the religion. It was an advertisement. Thank heaven my cousin, Jeremy, was allowed to share a poem that he wrote about our Grandmother. I sat there and gritted my teeth the whole time, and I know my family was afraid that I'd make a scene, but I didn't.