The director's statement that everything has been lost seems rather pessimistic. There must be some sort of digital catalog of what was present in the museum that'll preserve it in some form.
https://www.theguardian.com/world/2018/sep/03/fire-engulfs-b...
This is still useful data, for example knowing that a species used to be present in a particular area, but if a specimen is destroyed then in the absence of a photograph of the specimen (and sometimes that's not enough) the original assertion can no longer be verified.
https://www.gbif.org/publisher/4205110f-3f0f-40d8-bd0f-2fa71...
(I work at GBIF, so I know this data exists, but otherwise I know nothing more than the article covers. I do not know what proportion of the total biodiversity collection 270,000 is, whether they were stored in this building, or whether there are images of them. As one example, they estimate 550,000 plant specimens, but share data of 42,000. That might well mean it isn't electronic, or it might mean it exists in a database but isn't yet shared as open data.)
Also, you would expect museums to have digital catalogs of their collections, but that's not what happens in countries like Brazil.
I'm a Brazilian living in Europe and only when I moved I could see all the "basic" things we don't have. Access to art and culture in Brazil is something awful.
I'm not sure a some random commenter on HN can pretend to have a better perspective on the situation than the director of the museum himself.
I'm somewhat optimistic about the fossils too --- which are pretty much rock already, so relatively heat-resistant.
Even if they could survive the heat, most of the roof collapsed and at the moment the fire still is out of control...
I wouldn't count on it...