Father hears and "sees" people outside his home at night. No one is there. Is this hallucinations, delirium, or dementia?

Hi new here ...... My dad is 87 and in good health mostly. He is blind, and had a recent bout with lung cancer (successfully treated). He takes a low milligram statin and flomax. That is the extent of medications, other than eyedrops. He had a kidney infection recently (I know that can cause issues), but that seems to have cleared up. Last summer was hospitalized for prostate surgery, and suffered extreme delerium from the anesthesia at that time. That is the extent of medical issues. He lives in his own home, and has never had any problems, until the past month. He does have a woman that lives there to assist him with doctor appts etc, but she is not a caregiver, more of a roommate. Lately he says people are trying to break in his house, says he hears them and sees them (yes, he's almost totally blind, not quite but almost). He's called the police multiple times, four last night alone. The police don't believe anything is going on, and my brother and myself don't either. The woman that lives there says she hasn't seen or heard anything, but says that she doesn't want to humiliate him by telling him this, so she just humors him. I feel this is making the issue worse by validating his fears. He hates going to the doctor, and is insulted if we suggest it. I want to get him to the doctor by explaining that there could be medical issues causing his fear etc.... mostly because I believe this to be true. The recent kidney infection bothers me most, as I worry there is an underlying, more serious infection that could be triggering these issues. My father is an intelligent strong willed man - these things happen only overnight. During the day he is fine, other than believing the thing s he has "heard" and "seen" during the night. We had security alarms put on his house, as well as security doors - no one is going to get in - and that has alleviated his fear somewhat, but now says they are trying to remove the windows to get in. I'm at my wits end, I feel his roommate is making things worse (he is sitting up all night and she is sitting with him, even though she hears nothing and knows nothing is wrong). I feel she should be alleviating his fears, by going outside, even taking him out, to see there is nothing there not playing into them.

I know the real answer is to get him to a physician to be evaluated, but that will be no easy task, as I said he is smart and strongwilled. How do I get him to go? And do I insist she stop what she's doing, or am I wrong? I just don't know, neither my brother or I have any experience in this, and don't live particularly close, same general area of the state, but different cities.

I would so appreciate any ideas - I love my dad, but this cannot continue.