Alzheimer's?

My mother appears to becoming demented. She often loses track of the time of day if she naps during the daytime. At first, the surgeon blamed the drugs from the operation on her colon (a polyp which just turned malignant) After an adventure on 18 January, when she drove off at 2 AM to go to the primary physician at 10:15, she hit a gate and damaged the van. The police kept her until my uncle and I could go get her in Conshohocken.
It took a long time for us to get the vehicle repaired (damage of $2342 to the right front light and the area above the bumper). Recently, I took her to the primary physician, who gave me a prescription to a neurologist. The neurologist remembered her from the operation. He gave her a memory test in my presence on Thurday (23 February), and she scored a 26, which is mild(ly) (demented). He prescribed a medication called memantine for the next four weeks. We will be back on 23 March to assess its effectiveness. I take her for an electroencephalogram on 7 March. She hasn't spoken much about driving, and I have the keys hidden in the basement. Hopefully, the memantine will arrest the deterioration.