@JuanitaI727547
Your MIL is fortunate to have you. You are right to review her Medicare coverage with an independent agent.
However, since you mentioned her financial situation, it may be in her best interest for you to investigate whether or not she might qualify for "dual eligibility". Which means in a nutshell that she qualifies for both Medicare and Medicaid.
This article from AARP explains it pretty well even though it was written in 2018 - the program only has eligibility limits change from year to year otherwise the program works the same.
AARP - Combining Medicare and Medicaid - Dual Eligibility
If she qualifies for these Medicare Savings plans (Medicaid)in her new state - this may save the need of having the Medicare supplemental plan (Medigap), her prescription drug plan and maybe even paying her Medicare Part B premium.
If she doesn't qualify, find an INDEPENDENT Medicare Insurance agent/broker in your local area - they write policies for many different companies - Medigap, Prescription Drug Plans, Medicare Advantage plans with or without a built in drug plan.. Your state's Insurance Dept may have a list of these professionals.
It's Always Something . . . . Roseanna Roseannadanna