My mother is doing and saying crazy things and arguing with the grandkids. How do I know if she is getting dementia or if it's the medication she is on?

I would gather all of her medications and see a doctor. I'd ask both the doctor and the pharmacist for drug interaction reports. Then, I'd see if the doctor is willing to experiment by changing some meds. This has to be done under a doctor's guidance, but you could be on to something. If her meds are okay, and she has no infections or anything, she should be tested for dementia.

Good luck,
Carol