Well, yes, you can't use any digital currency if you don't have electricity/internet, XMR is not magic 🙃
But nothing prevents you from sending XMR to someone who organizes fundraising (e.g. for buying & delivering water to those who need it) from a place where they have electricity and internet access.
XMR is digital cash. How does putting cash in someone's pocket help them in a disaster? It's a transfer of value that no government can prevent, but how does it actually help those affected?