My dad’s been in a care home since Sept 2018. He has no mobility from chronic myopathy. When I asked my siblings to help find a place as he needed 24hr care everyone left it up to me. I found a clean place he can afford with only 6 clients so he gets the care and attention. My dad is being taken care of and he’s happy. To me, that’s what matters. My SIL claims she would have taken him in and cared for him. My dad doesn’t care for her so that would not work. She’s always trying to stir things up in our family and I’m getting sick of it. My brother never says anything.
I also have to declare up front that I am no longer in touch with my SIL. It's safer that way. For her.
But my SIL was actively undermining my mother's care, and actively interfering, and (unintentionally, I acknowledge) did positive damage to her (this is all over now, it's not an ongoing issue, just one for which I will never forgive her or my brother).
Your SIL - unless there's something else? - is merely shooting her mouth off and talking b.s. and being a pain. Your brother presumably finds it easiest not to rise to the bait.
You can
call her bluff, and ask her when she'll be making the necessary arrangements
tell her she's full of it
ask her to stop making you and the rest of the family miserable
tape her mouth up
or
can you avoid her, so that you don't have to listen to this?
I had a SIL that pretty much ignored my family. When I was setting up a 50th Wedding Anniversary for Mom and Dad I called brothers house and SIL picked up. I asked to talk to my brother than proceeded to ask him if he would go in on the cost. SIL called me later and asked why I didn't talk to her. I told her because they were my brothers parents.
As this was not blood relative, and he did nothing to help, it was terrible. I never said a WORD to him, and DH simply rolled over and let BIL and SIL have whatever they wanted.
I do not regret taking the path of silent acquiescence. I know what to expect when DH's mom dies. The same.
Fighting with someone---esp family---not worth it.