Persons with Alzheimer's or other forms of dementia are prone to argue - some more than others. This may frustrate caregivers. What seems to make perfect, logical sense is no longer logical to this person? For instance, why does mom want to go make supper for the children when she now lives in a care facility with no children to care for? Why does dad insist he can drive, even when a bent fender shows otherwise? This is the disease.
People with dementia lose insight to reality, forget events or may start to mix details, and become disoriented to time and place. Their arguments come out of their current reality. For mom, in the previous example, she is living back in time in this moment and the kids need their supper. She may not rest easy until she is reassured that they have been fed. Perhaps she is told the kids are eating at the neighbor's house tonight. Dad, may be a harder case to verbally redirect. But you may disable the car engine or create a flat tire when he is not around, to diffuse his desire to drive when it comes. Arguing back with the person who very strongly believes in the time and place they are currently experiencing does not work and will usually make it worse. Instead try to redirect (like in the example given above), reassure, and remember it is the disease. The caregiver can communicate to the reality that the person with dementia is experiencing right now, to minimize arguments and anger and maximize reassurance and happiness.