@RebeccaBoyd play her some of her favourite music from her youth. Neuroscientists are discovering it can be amazing therapy.I’m so sorry you’re dealing with this, it’s such a hard situation
Maybe try sharing some resources on talking to people with dementia with her brother and her other visitors. Something very small may have set her off. This really isn’t that uncommon from what I’ve learned about living with and caring dementia patients. If you can learn the triggers and surround her with things that keep her in a happy place it makes things easier. You never know though, sometimes the complete change from “normal” of going into a care home can really change things positively as well. Complete strangers are strangely less likely to trigger negative reactions. My grandmother, surrounded by strangers, with no expectations of her to remember them, simple routines, and games, was much happier in her final five years, with very few moments of fear and paranoia.
Remember this is a huge adjustment for everyone in the family. And Grandma’s probably very afraid too.
With my mom I’ve been working on not saying “remember” at all in conversation, and this tiny change has helped with the hostility. And not arguing with false statements like “I’ve never seen this movie before” (it was a favourite from the Nineties, we watched it at least a dozen times!) and I know damn well the last time she rode a horse was when we went for a trail ride on vacation on a whim when I was 15… and focus on the things that being out the good memories of childhood/youth. Music and TV shows can be great tools. The chickens are clearly one of those as well.
