I see you are in MA. If that is correct and the rental property is in MA there are several programs out there that should be able to help her. However, my understanding is that not only does she need to apply and meet their qualifications, but you may need to start an eviction for her to have a paper trail to prove it to these agencies.
She should contact the local housing court for information about these programs now so she knows what is required of her. These programs will reach out to you as the landlord to verify rent etc. so be prepared for that.
But if you don't hear from any agency or her and it's January 1 and no rent, start the eviction process ASAP as it will take some time to work through the system. She will have another chance to apply for help from these programs. You do not want her to run up a big debt. COVID is over and these programs are back to limited money. I think the limit on one program is now only $7500 which doesn't cover a lot of rent.