Need to hire an experienced healthcare advocate to manage my mother's medical, and Medicare needs, work with doctor's and keep me updated.

Aginglifecare.org

You can hire a geriatric care manager if you live in a large enough area

I would start with contacting/looking for patient care advocates through professional directories such as National Association of Healthcare Advocacy or the Patient Advocate Foundation's directory.

Your internet is going to be your guide, and A.I. is going to give you some guidance as well.

This is expensive stuff, so not an ongoing thing like a Fiduciary hired to manage care placement, bills, payments, and etc. The hourly fee usually involves managing special health care issues.

It would help us a lot here if you would let us know EXACTLY what your mother's issues and needs are that either she cannot handle (and the reasons she can't) or you and other family members can't handle. It may be closing in on time for ALF where a lot of stuff is handled regarding medical appointments, checkins and checkups and etc.

I feel a bit at a loss as to your needs here, so I am leaving you to research a bit online, and I am wishing you luck. And if you find just what you need I hope you will update US here with what you found, what you learned, what costs and help you found to be the case.
I hope others here will have more for you than I do.