The empty Chair by the window

"I was at a family gathering, although I couldn't tell what we were celebrating. Everyone was talking and eating, but there was an empty chair near the window that nobody seemed to notice. I kept expecting my grandmother to sit there. I even put a plate in front of the chair because she always used to complain when people forgot to serve her. Then I realized she had been gone for years, and the food on the plate suddenly looked cold. I walked through the house looking for her. The rooms weren't quite right, and every time I opened a door, I found a different version of the same living room. In one of them, she was standing by the curtains with her back to me. I called her name, but she didn't turn around. I started telling her everything I hadn't gotten to say, though I couldn't remember the actual words. Mostly I just kept saying that I was sorry I hadn't visited more. When she finally looked at me, she smiled and asked whether I was staying for dinner. I said I couldn't, because I had to go home. She nodded like she understood. Then I woke up crying, with the feeling that I had left her there again."