Sunny,
You may know this, but if your mom advises her doctor in writing that he can discuss her medical care with you, you would be able to talk to him directly.

My grandmother suffered from dimentia, although she was not one to go to doctors at all. She would agree to see the ophthalmologist for glaucoma but that's all.
She did hear things and thought her neighbors could 'broadcast' into her house. She accumulated reels of tapes, "evidence" for the police that she would play for them: they contained nothing but the static noise of the machine used to record.
This started not too long after her husband passed away. She was very afraid to be alone, but would not move from the house.

Later she was convinced that people on TV could see and hear her. (This one is cute) One night I arranged a babysitter for after work and took dinner out to her place. She liked to set up a card table in the living room, so that's where we ate. Shortly after starting, she turned around and turned off the TV and I asked why. I thought we were both watching the news. "Well, it would be rude!" she said. I asked her what would be rude? "It would be rude to eat in front of him!". She could not be swayed and went on to say that Vanna White could see her too. "Why else would she wave?!".
And so, when Vanna waved, Grandma waved back