I also close the living room and bedroom drapes in late afternoon and typically have all the lights on where we sit in the living room. However, eventually that wasn't enough and my husband's behaviors and nighttime delusions became worse and I talked to the doctor and he was given Seroquel at a small dose and then eventually increased a bit. That has helped tremendously and we usually have quiet days and delusions don't happen very often anymore.

If home, while still very light. Turn all lights on bright
Pull all curtains/blinds closed.

I haven't found a way to help my husband through sundowning. Nothing seems to work. He just goes through phases that sometimes are difficult and days when it doesn't occur. I just have learned to expect that it will sometimes happen.

Agree