Beaker has thrown up a few times over the last couple of days, so we took her to the vets this morning. Had bloodwork done - her kidney function has decreased dramatically, and she's now badly anaemic too.I've been through something very similar just a couple of weeks ago. My Jack Russell, Bunsen. 15 years old, and has been suffering from dementia for maybe a year. Finally had to accept we were doing him a disservice by not taking action - there was little quality of life remaining. If he was awake, he would just be constantly circling, sometimes quite frantically.
He had to be sedated, because he was too confused and anxious to be canulated. After a bit of wandering around the room (similar place to what you describe) he came and lay across my leg as he fell asleep - which nearly broke me.
I got through the procedure, had a bit of a meltdown when they left me with him for a while afterwards. Then another when I got back to the car, and another when i got home.
At the time, they asked if I wanted them to take pawprints and a clip of hair for us to keep. I just said I don't know, as I was too numb to answer and they dropped it. Last week a sympathy card arrived from them with the prints and hair inside. Apparently I should have said yes, because seeing them broke me again.
I'm getting better, but still keep feeling hopeless when I remember him and his last day. Like you, we have the benefit of his sister Beaker still being with us.
Any treatment they would give her to improve one of those, would likely make the other worse. And analytes for both are now more than 2x ULN.
It's time to let her go. This wasn't part of the deal when we lost Bunsen. Beaker was supposed to last at least a couple of years to let me recover.
She's on anti-emetics for now, to stop her actually feeling terrible. It's hard to plan what will impact all the family the least badly, but I think I will be taking her in either tomorrow or Monday.