Can Prednisone alter behavioral patterns in elderly patients?

Hi doctor,

My question is regarding my grandmother. Lately, she has been acting differently, not her normal self, and the change in her behavior has been about two months now. She talks about things that do not make sense. She sometimes acts like a small child. She does pointless actions and always does something to stay busy when she is supposed to rest because her feet are extremely swollen, with leaking fluid and blisters. Apart from this, she is forgetting some things (like forgetting that my sister was coming over to stay and also forgetting where she kept her dentures). I am not sure what kind of doctor I need to consult. She has seen her PCP, and he has not offered any explanations or solutions. She is on the following medications, Prednisone, Crestor, Levothyroxine, Hydrochlorothiazide, also Insulin for type 2 diabetes. A blood test that was taken five years ago revealed that she had a biopsy done, and they said there were suggestive findings of giant cell arteritis. They did think it was the Prednisone she was taking but have lowered her dosage from 30 mg a day to 10 mg a day. I need a guide as to what my next step should be.