It seems like forever since I've seen one other than in pictures. At my house I make sure the blinds are closed and the lights turned on before sunset in order to minimize my mom's sundowning from vascular dementia. It does seem to help, but man, I miss those sunsets.
I do wonder if you're taking the term "sundowning" a little too literally. It is after all only a metaphor to describe the distress and anxiety caused by sensory deprivation which has been shown to be exacerbated by diminishing light levels. It isn't that witnessing the sun itself go down will trigger behavioural problems.
Is your mother mobile, or in a wheelchair? You could probably do worse, once the weather becomes warmer, than to take her outside with you and the little ones to enjoy the fresh air and scenery.
My mom has COPD as well as vascular dementia, so she is not very mobile. I'm in the process of getting her a transport chair and a walker with a seat. The walker for using around the house and the wheelchair so that I can get her out and into the world.
I do plan to take her out on the patio once it is warm enough. I have yard work to do and she can spend time outside with the furries while I work.
Thank you so much for your response and your suggestions. I really do appreciate them!