There is no indication they're working with archive.org or any other preservation charity yet. The only way the artwork is going to be saved is if it's moved somewhere — and with help from the people who love their work.
Ask the artists if they're willing to have their art backed up on a booru. Use shouts, so they only get asked once. If they say yes, spread the load among several (such as e621 and furbooru ). Try to preserve original titles and descriptions (we request that in our own uploading guide and our Esteemed Companions on the internet have their own for their own sites). Please be sure to tag accurately and completely.
Ultimately, everything on the Internet is built on sand, and the waves are always coming in. But we can keep telling their stories to keep a little of it up a little longer.