hi..well, if he has delusions and talks irrelevant, he should consult a psychiatrist
..moreover, a brain-imaging should be done fresh..there may be dementia
..a possibility of Lewy Body
dementia where visual hallucination
is common..for the other psychological symptoms, there are atypical anti-psychotic available although excess sedation is a complaint ans you have to monitor closely..so consult and help him to feel better..thanks..