My dad saw a ghost of my grandfather right after my grandfather died, but it was BEFORE my dad even knew that my grandfather was dead. The grandfather gave a message saying "I'm fine. Keep on going and properly raise your kids". My grandfather died when I was 5. At first, I thought he was crazy, but after searching up ADCs I knew that this was a normal phenomenon. What we can't explain is why some people see dead people before they even know that they are dead, or why 2 people can sometimes see the dead person in the same place.
I always have seen holographic life reviews of events that took place 1 week ago to 2 years, and the events were always real events that happened, just like how life reviews are described in NDEs. Usually, this happens during the period of waking up from my sleep.