@William633
it's extenuating circumstance so your guests would be refunded for the rest of their stay if they contact Airbnb, explain the situation and ask Airbnb to cancel the rest of their stay.
Or to keep it simple, you can send them an alteration request (change or cancel the reservation) and shorten their stay. They have to accept it. (or they can send the request to you and you have to accept) The difference in the price you can refund them through the resolution center (send and receive money) They also have to accept it.