I had to take my wife home because she was sick herself at the time the two of us were visiting my mother at the hospital. I told my mother, "I'll be back in a little while," but I didn't explain why, and with her Alzheimer's, she probably wouldn't have remembered anyway.
.Just moments after I returned to the hospital alone, mother took her last breath. At least I was with her at the time, and she knew me, but it really troubled me that she must have wondered why I went away for a half hour or so and left her alone.