Hello Gladys
Sorry to hear about the time you are having, it's awful, isn't it? The pain of seeing a loved one struggling with no answers to give.
I care for Mum, 81, who has been in a nursing home for the last 18 months, following us caring for her at home for many years. Like the other members, I understand a little of what you are experiencing with the sundowning.
It won't do any harm to your Mum to be taking her 'home' but you will be out of your own mind if you start this, because you will never stop. As an illustration: Dad started to take Mum back to her chilchood home (the house is still occupied by her nephew) and she'd arrive outside, ask what she was doing there - didn't want to be there, and Dad would bring her back to their home only for her to start again, she wanted to go home! This went on for many months until Dad was at breaking point. It's not the bricks and mortar she is after, it's 'home' and all it means to her - her mother and her childhood which is where her mind is at that moment.
I discovered that my Mum was, in fact, worrying about HER Mum (don't for God's sake tell your Mum her own mother is dead if the occasion arises, she will go into mourning because it will be new to her - a huge mistake I made at the beginning which I deeply regret to this day). I learned to play the game, go with the AD. I would tell her that her Mum was fine, had just called in to see her and she was making an apple pie and looking forward to seeing her later, or variations thereon. It worked, still does, although it works better now that she is on medication that calms her.
It took me a long time to cotton on, though, with many tears, much frustration and trying to reason with the unreasonable. Maybe this tack will help. You know your Mum best so try to create the cosy familiar scenario at her home to make her feel secure, telling her everything is OK, nothing to worry about, and she will hopefully move on until the next time. The secret is not to fight AD - a fight you'll never win - but to go with it, play its game, however painful it may seem at the time.
I hope that you can find your coping mechanism to help with this time. Take good care of yourself too in all of this, you are very special, don't forget it!
Many best wishes
Chesca