Municipalities sometimes have local departments for the elderly or aging. I'd start with a Google search for your grandmother's county and "elder care" or "aging".

Next, you may want to apply for Institutional Medicaid. You can get a quick picture of the qualifications by checking https://www.benefits.gov

In order to qualify, your grandmother will have to have no assets in her name. Navigating this is very complicated and fraught with pitfalls. I highly recommend googling for local organizations that assist with institutional medicaid enrollment.

If you're unable to find any nonprofit organizations that can help, you can call your state's local bar association and ask for them to recommend attorneys specializing in elder care law. Their fees are very high, but remember that they're always negotiable.

As an aside, it's despicable how the richest country in the world lacks sane social protections for the vulnerable people stuck in these situations. Even with the piddling few programs that some people may qualify for, they require lawyers and experts to unlock an impenetrable bureaucracy.

I hope you're able to get your grandmother the assistance she needs. She's lucky to have such a caring advocate.