Where to find a local Dr to monitor a dementia patient?

You do not want a PCP to monitor Dementia. For me, PCPs know a little about everything and a lot about nothing. You need a neurologist to diagnose what type of Dementia it is because of medication. Once diagnosed there is not much more that can be done. My Mom was easy and her Dr was not big on medication unless needed. She had her paranoia, but my daughter was good about calming her down. Hallucinations, she saw a little girl she talked to. I was told if the hallucination did not bother her, then not to worry about it. Some people suffering fro Dementia do get aggressive so need meds to calm them.

Have you spoken to the PCP for a referral. Sometimes it accelerates the wait time

if you gave a local Alzheimer’s support group (see Alzheimer’s website) you can find other caregivers with similar concerns to connect with.
Personal referrals can be the best resource.

When you say "monitor" a dementia patient, do you mean test and/or diagnose that person? Or someone to do ongoing oversight of that person?

You can look for a Geriatric Care Manager, or go into your clinic's portal -- they usually list the available doctors and their specialties, and you can make an appointment within that portal -- or they give phone numbers to call to schedule.

Nextdoor.com is a good intranet forum of your actual neighbors and near community. You can join it and ask for recommentions for a good primary doctor, internist, geriatrician, etc.

You signed up to a chat forum of caregivers to elderly loved ones from around the world. We cannot help you find a local doctor, you can Google that info. Good luck.