When I was a teen, my grandfather had alzheimers, a failing heart, and half of one lung. He was covered with scars and sometimes muttered at walls.
I was asked to keep an eye on him, briefly, one afternoon, while my grandmother did something else. While I was alone with him, he looked at an empty space right next to me, and whispered: "Mom? Dad? Is that you?"
With the exception of getting hit by a car, that was the most terrifying moment of my life.
Scanned from one of last years sketchbooks. Micron pens for basic sketch, added shadows with Koi watercolor pen, and used acrylic paint for the green background.