My mom lives at MCF and is in late stages of AD, she's recently started telling me stories I'm not sure if she's having hallucinations..

Mom told me a story today about my brother being at her MCF (Memory Care Facility) last night with a girlfriend, but they weren't visiting with her but other people that were there. She told me how they made a scene by being affectionate and how everybody was asking her about it. She says that she DID NOT visit with them. She wasn't upset, couldn't really articulate exactly what happened but just that it was not appropriate behavior to have in the dining room area of her wing and did I hear about it? I just went along with her story and listened. I know that the later stages of AD can bring hallucinations (and I don't think that's what she was describing to me), story telling and other behavioral changes. Although this isn't the first "story" she's come up, there's been a handful of them in last few weeks but they all seem harmless and out of the blue. My brother is married and wasn't there last night. I'm not sure if my mom saw someone last night who looked like my brother with his family and she is recounting that or if it's all just made up for some reason or if its an indication of what's to come or all of the above.... If anybody has any experience/insight with this "story telling" and how you handle it that you can share I would really appreciate it. Thanks in advance!