Your father is 93-years old and has been having dementia for several years. I presume he is admitted in the hospital with a medical illness. Elderly people with dementia who have a concurrent medical illness are very much at risk to develop delirium. It manifests as sleep-wake cycle disturbances (typically a reversal or sundowning), agitation, hallucinations, confusion of thinking. The mainstay of managing delirium is two-fold: 1) treating the underlying medical illness (antibiotics for infection; dialysis in those with renal failure etc.) - which I am sure is being done. 2) symptomatic treatment of delirium. It requires antipsychotic medications in low dosage. Trilafon (perphenazine) is an antipsychotic drug and can be used for his condition. It is risky to use psychotropic drugs in elderly, but the benefits of using them in delirium may far outweigh the risks involved. This is because it is given in low doses and for short periods of time. A delirious patient is at risk of harming himself by his agitation (eg: the repeated falls due to frequently waking up).