My mother is 90 yrs old and has dementia. She lives with me, and the most troubling issue I have is the constant questions asking where she is (my home), where is her car ( sold 3 yrs ago) where is her dog (he lives with a relative) how long has she been here etc... She has very detailed "stories" about walking to another house, or seeing people that havnt really been there. Sometimes she thinks she drove her car and left it parked unlocked on the street and or left her house unlocked and the door open, last week she she got very panicky thinking she left a baby all alone in her other house. So I guess its not just the questions, but how to deal with the "stories", she becomes extremely aggitated when I have to tell her some of it isnt real.
When she gets concerned about leaving her house with the door unlocked tell her, "No mom, you locked the door. I saw you lock it." Or, "Mom, the baby's mom came and got her. She's not alone now, she's with her mom."
We can't expect our loved ones with dementia to be in this world with us. They're not capable of it anymore. We have to go into their world to take care of them. Just placate your mom, soothe her, reassure her, and she will probably stay calmer than if you tell her that these things never happened.