@Nur666 A host always has the option to agree to refund a guest or agree to a date change or to offer to refund any dates of your booking that they are able to rebook (but those dates are blocked to rebooking by your reservation until you officially cancel)
But hosts are not obligated to do any of that. A guest is bound by the terms of the cancellation policy stated on the listing. That's why travelers take out travel insurance- to cover themselves for unforeseen travel disruptions.
So the host is quite correct- it is up to Airbnb to decide whether your circumstance is eligible for a refund if the host isn't willing to refund themselves.
And FYI, hosts do not get paid until at least 24 hrs. after a guest's check in date. So the host does not have your money, Airbnb does.
There is a pinned post right at the top of this Help section of the forum as to how to contact Airbnb.
You should gather any official govt. travel warnings concerning the flooding, so you can present them to Airbnb.