My 88 year old Mom has dementia. Lately the paranoia has gotten worse. She hides money all the time. Has done so for many years. 4 sibs are taking turns staying with her 24/7 in her 1 BR apartment , sleeping on an air mattress on the floor in the living room. She is delusional and hallucinates about strangers coming in and out all day, every day. I think she's confused because it's us caring for her who are coming and going. Shes been been all over the apartment today looking for something. Found out she's looking for the money she hid. Says she's tired of these people living here, not paying rent and eating her food, not to mention stealing from her. I said Mom, no one would ever take anything from you. That got me nowhere. It's like shoving a stake through my heart. Btw, she ALWAYS. finds what she's looking for. Have you dealt with this with any success?
Be sympathetic without actually agreeing that things have been stolen. "Oh, it must feel so bad that your money/glasses/paper towels are missing now. I wonder if I misplaced them by mistake. Let me help you look for it."
I wonder if Mom would like to have a simple fire-proof box with a lock? She could put her money in it, and keep the key on a chain or keyring. This is a "logical" solution and logic may no longer appeal to her, but it might be worth a suggestion. At least it will help her feel you are on her side.
Paranoia and delusions are both hard to treat, but all symptoms should be discussed with her doctor as they come up.
Oh, but she claims she never "hides" anything. And when she finds it claims someone else put it there.