@Shannon264 You DO NOT help them you will get penalized and your dates blocked and have a cancellation on your record so no superhost for a year. The guest needs to cancel then if they have legit extinuating circumstances AirBnB will give them a full refund. Do not ACCEPT anything you may receive regarding the cancellation. DECLINE only.
FYI for now and the future:
DO NOT CANCEL a reservation, DO NOT ACCEPT any message about cancelling, changing or refunding DECLINE it a loophole that comes back to bite you and gives guests back their service fees and/or voids your cancellation policy (changing dates) or the cancellation is now on you, not the guests (accepting cancellation). DO NOT REFUND anything until actual cash has been given to you by AirBNB. If you refund they will take the money from you and a lot of times guests get refunded from both AirBnB and you if you do this, then you have a fight to get your money back. Tell the guest you do not deal with the booking funds that is all on AirBnB's end.