@Dallas15 He will get refunded according to your cancellation policy, which I see is flexible. So if he made this cancellation less than 24 hours before check-in, he will be charged for the first night, and receive a full refund from Airbnb, minus service charges, for any additional nights. So what Airbnb is trying to get you to do, because they love to pander to guests, is agree to refund the first night. You can, or not, it's up to you. But don't refund anything until you have actually received what you are due, in case the guest manages to get Airbnb to give him a total refund.
My personal feeling on this is that I will refund in certain cases, but I would keep enough to pay myself for any time I spent dealing with the reservation- whether it's messaging with the guest or preparing the space for them. If you depend on this income, like to be as fully booked as possible, and don't have time to rebook the room, don't refund that first night. Also you might want to look at changing your cancellation policy to Moderate.