I've known a cat that had what could only be described as feline dementia. He used to wonder round the house yowling as he didn't know where he was, and after feeding would forget he was fed. Only thing that calmed him was his owner who say'd "Cat (I forget its name) you're fine, go to sleep" or "cat you've eaten" and it used to calm down and often slept when told to.
Maybe something like this would work? If she can hear you, then she might be less weird? And to make life easier for her I would keep things where she is used to them. I would also consider turning her into a housecat, with a harness for outside time, as I would be worried she would get lost, or hurt.