Question about computer from 2012 that used to mine BTC

Hello everyone. I just learned that my Dad used to mine bitcoin on an old computer that we still have. He mined from Feb 2012 to 2014. I have searched the computer for a Wallet.dat file and havent found anything. However, there is a crypto folder from 2012 that I assume is linked to the mining. In it is two other folders named "RSA" and "Keys". In these folders are a bunch of .sys System files with names of random 64 length numbers and letters. 0-9, and a-f. He said that he thinks he used an online wallet. I assume that the website no longer exists, and even if it did there's no way he remebers any passwords. Does anyone have any tips to try and find if there's any recoverable BTC? I assume that the only way to get it back is to have the private keys but I'm not sure how to find them. I'm sure it's close to nothing in USD but it would be awesome to see how much he had. Thanks!