Medicare and insurance options in the United States... I'm looking for advice

Go back to straight Medicare or keep a supplement?

Hello! My mother has had mild/moderate dementia for 10+ years and now is the time that we need to renew or change her Medicare part C/supplement.

Her neurologist once told me that her insurance likely wouldn't cover the PET Scan she needed because she didn't have regular medicare.

The insurance did cover it with a relatively small copay ($250) but I'm wondering If It's smart to go back to regular Medicare for now, in case she needs to move into a facility that can provide support to her.

I know straight medicare doesn't cover vision/dental/hearing, and Medigap can deny pre-existing conditions.

Ironically, she refused the PET Scan, so I'm not sure the type of dementia she has, so not sure what is to come...

She has had Essence insurance for the past few years. Any insight or experience?Thank you!