Tall Dark Figure

by Keenan
(Reno, Nevada, USA)

So I would be sitting on the couch and 10 or 15 feet to my left is a hallway and sometimes I would see a tall dark figure pass through the hallway. It happened for a year or two until my grandpa died a few months ago and i haven't seen it since. It looked about six feet tall can anyone explain this?

NOTE: My grandpa lived with us and he would always talk to someone that wasn't there and say "I'M COMING HOLD ON!" and stuff like that. Can anyone explain why as soon as he died the figure stopped showing up?