Old man is one of the Cannibals in the Mansion in Lakeview Cabin IV.

He is seen relaxing in a worn-down armchair in the Trophy Room. Next to him is a clock which opens a secret door if you active it.

When you enter the room he is facing the other direction so he's unable to see the player, making the room easy to pass through untouched.

But watch out for blade traps which are more likely to spawn in this room. Sometimes there is also a rug trap in front of his armchair and when you sound the alarm there is a chance he will fall in the hole.