OP is working as “help” in a nursing home. Legal fees will never be recouped.I mostly agree and I'd leave one way or another. But if these allegations are false or unproveable, the OP might want to confront HR regarding the allegations. "What proof is there? Why weren't police notified? You have thieves but do not fire them immediately? Wow, you really do protect the residents here, don't you?". Just "write up" them?
It seems a bit sketchy if not illegal. You can't just say whatever you want without recourse as there are federal as well as state laws. Also this employer may tell future perspective employers that he's a thief to blackball him.
Consult a lawyer and have a service call the employer after he leaves for "a reference".
IMHO, if I am innocent and didn't do anything, I'm looking to leave with a settlement...