@Erica1334 How long is his reservation for? I would send him a change request to shorten the reservation since he doesn't like the space and is obviously angling for a refund anyway, which he might get no matter what you do. So, better to get him out ASAP.
This is a lesson. We have found, and I think many/most long time hosts will agree that guests who start off asking for extras and favors=poor guests. As you found, you gave him the extras and not only was he not grateful, he expects more extras..extra guests and a dog in a no pet listing and disrespected you by contacting Airbnb directly.
We still offer guests extras like early check in or late check out [although the last guests we gave late check out to repaid us by having burned the kitchen table and never saying a word about it, so even long time hosts can be wrong about the guest].....but now we do it on our terms. If the guest seems nice, is nice, then we offer some extras if it is convenient. If they start off wanting an early check in or other extras, we say no.