No Caz, I don't believe in them, actually.
But there is one incident that I do remember. My great grandpa was on his deathbed and was just a few seconds away from dying. He said, "Ahh, the doctor has come. Tell him I'm not feeling too good now." And that was it. He was gone. But actually, no one had entered the room. In our religion, they say that just a few seconds from dying, you see a spirit or an angel or something that has come to take you to heaven. I don't know how far that is true but my family members say that he had seen that and thought it was the doctor. I was too small to understand all this and didn't really know what to believe..
I can totally accept that what your granddad saw was indeed a spirit come to lead him to "the other side".
I recall a similar incident. The day before my mother died she told me that my father had walked down the ward, stood at the foot of her bed briefly and then walked away again. Weird? My father had been dead for over five years! I reckon that in his own way he was saying that he was waiting for her to join him.