In my husband's case the puzzled and worried behaviour starts regularly, about now, exactly as the sun goes down behind our hill. At the moment he's happily filling a jug and going in and out to water plants and fill bird baths. I can predict that within half an hour he will be more anxious, and will be asking me to explain just exactly what's going on, and he won't understand the answer. This will happen over and over and over...until bedtime, which may be brought forward if I'm finding it hard to cope with. Then he will ask me if doors are locked and the windows closed over and over and over and over and over. Such a shame on a lovely summer evening. Luckily, I have a good book.