@Berit16
Don't cancel and make sure you keep all communication on the Airbnb messenger.
If it were me, I'd say tell the guest whether they cancel or not is completely up to them but the cancellation policy will stand as agreed on when the guest made the booking. This would be the same whether they have a reservation with a hotel, Airbnb or airline - rules are rules. And just to make sure they completely understand, I'd reiterate that as a host "I (you)" have no intention of cancelling the booking. If the guest needs to cancel, then it is THEIR responsibility to cancel.