which MD speciality would be best for a dementia patient?

My spouse was diagnosed with MCI first, then she progressed to dementia a few years ago, otherwise she is physically very healthy. Yes, she did go through all of the tests for the diagnosis (including a PET scan). She has been under the care of a neurologist and seeing him every 6 months. she has also tried all the current drugs but only mematine (not the plus) seems to be working. she does not want an infusion. My question is: which MD specialty is best for her? neurologist? geriatrician? or some other specialty? I do not want an MD who treats her as a guinea pig but a valuable family member. Yes, we have met a few MDs who wanted to use her as a guinea pig.