How to find a Geriatric Doctor?

https://doctor.webmd.com/find-a-doctor/specialty/family-practice-geriatric-medicine/new-york/yorktown-heights

Google your location and geriatric doctor or geriatrician. You will find links such as the one above.

A gastro doctor recommended my aunts.

Call your closest teaching hospital or call the best nearby hospital-affiliated rehab facility and ask.

I have gone on the website of local teaching hospitals and look up the geriatrics department to find a suitable doc.