Yes. My nephew was in a coma from an ATV wreck. When I was visiting him, I would brush his teeth because I’m obsessive about brushing my teeth. When he came out of the coma, that was the only thing he remembered.
Also when my mom was in the hospital dying, in a coma, we all took turns being with her, but there were at least 3 of us there at a time. As @SuperMouse did, we would take turns telling her it was okay to let go. She held on 11 days. On the final day, I was alone with her, the only time I had been. I sat with her and she just passed quietly. I really think she just wanted it to be me and her.