Hello! Im very concerned about my father who is getting ready to 62 years of age. I moved him down from Chicago last June to stay with me & my husband & two small children. Reason being is because he had called me & said that there were cameras put in his apartment, So the other tenants can spy on him & he had said he recently just got out of the emergency room. He said that one of the tenants broke into his place & poisoned his potato salad he had in his fridge. well he moved in with me & did nothing but sleep all day & stay up all night. So I found him a one room apartment hoping he would help his self accomplish in getting a job & etc. Instead he complained that there were cameras in his room & even called the police & told them another tenant was poisoning him with gas from the stove. So I moved him back in & he continued to do nothing at all. So I sent him to stay with my brother & he said there were cameras there & someone was trying to poison him with carbon monoxide through the vents. Now he is staying in a shelter which is helping him find residency & a job, which is very good. But is there some illiness to what he is imagining? Ive wore myself out trying to find out why he is thinking these things & actually believing them. He is a veteran & goes to the V.A. But can you help me solve what  his condition is, so I can understand?
As per reported by you your dad seems to be suspecting tenants trying to harm him leading to distress. He also seems to have alteration in sleep wake cycle and definitely not a normal routine. However, does he also have any other psychotic symptoms like hallucinations or any other behavioral problems? How is his interaction with others? Have you noticed any recent onset memory deficits in him, especially recent memory loss, or other cognitive tasks like handling money, buying things, going outside at public places alone? Has there any previous such episodes in past? Is he having any other medical illness or on any long term medication? Getting information on these questions is vital before reaching any conclusion. However, if he is willing to consult any psychiatrist or neurophysician its worth doing it and get evaluated at earliest as there is strong element of possible dementia vs late onset psychosis.