When my dad was in his 90s, for five years I spoke with him on the phone long distance on a daily basis. One thing we both enjoyed was I'd ask him what he could see in front of him and he'd describe either things in his room or outside. Sometimes he'd get his ruler and measure the size of something so he could tell me more exactly.
Our relationship changed with our talks to where we became confidants. The altitude he had as my father was intact, but we were communicating personally, closely as friends.
I would never invalidate whatever he told me. I'd just listen and let him know I heard him and understood what he said--just like we all need, he just needed someone to hear him. He didn't need advice. He didn't need to be corrected. Just needed to be let know he was heard and understood. That's probably one of the greatest ways I could repay him for his help all through the years. I made it safe for him to communicate about anything.
When my father was 96, I was home visiting for his birthday and Father's Day. He was in good shape, not ill. On Father's Day he said his final goodbyes and went into a deep sleep, as if unconscious. I leaned close to him and asked him a question and he opened his eyes just a slit, and said "yes." I knew he was "there." His body was going through what it was going through but he as a spiritual being was aware.