Site admin passed away…help!

Really hoping someone can point me in the right direction. Sadly, our site administrator passed away suddenly last week and now I’m rather stuck as to what to do as I do not have full access to our WordPress site (and am not particularly knowledgeable about it).

I don’t even know his user name let alone password!

I do have limited access, but not the full editing rights.

Does anyone know what I can do or what information I’d need to find out in order to do anything? All help greatly appreciated!