@Margaret824
I think case managers will first discuss situation / solution with the guest, which can take some time if guest is unresponsive. They can not cancel a stay because a guest is ill. Also there must be proove that the guest a safety issue. maybe talk to the guest and offer to shorten the stay ("change" option in reservation), it will refund remaining nights. Or maybe discuss hygiene standards with guest.
If nothing helps you can cancel the reservation, forcing guest to leave, but it brings penalties from Airbnb with it (and bad review from guest)