As has been wisely suggested, an infection can bring about hallucinations and delirium. Other factors can contribute as well. I learned not to question nor contradict this occurrence because that can alarm. Later stages in dementia often accompany hallucinations of a varying nature. I remember my mother becoming almost frantic trying to pull off sticky plastic from her hands. There was nothing whatsoever on her hands. I soon learned not to say so. That was prior to any diagnosis. Consult the GP.My father in law is seeing people who have passed away, he thinks they are right by him, this happens very frequently several times ever day and in his sleep, can the GP help with this?
He had a stroke about four years ago and has vascular dementia.