Sentinel in the skyway

An old man is sitting ahead of me in Starbucks, and dressed in mismatched plaids and stripes. He casually watches as the employed wander by him with places to go. He gets up to get another cup of coffee and sits back down. He crosses his legs and watches the flow of foot traffic as it wanders past the window like a waterless aquarium. A woman, who appears to have interacted with him in the past, knocks on the pane and waves at him. He smiles mildly, revealing pink gums, then turns and stares again in another direction without a word.

How did he get this way? He is obviously not competing with the people on the other side of the glass. There is no rhyme or reason as to what captures his interest. He stares at random times. I think of other older people I know. I think of my work at a nursing home. They all stare, as if the world has moved off tilt.