So now I am not sure what to do, should I just keep it or try to open and see ( i really doubt there is anything there ).
The matter is quite clear, you got access to the computer, and now you just need to get permission to load that file and see what's in it - of course, do it in the presence of his parents.
If there are coins inside i won't be able to use/transfer them without pass and bruteforce wont probably work.
Maybe you found an empty wallet, and maybe the wallet doesn't have any protection - even if it does, maybe you'll find the password somewhere in his personal belongings or on the computer. In any case, whatever you do, be careful not to download a fake wallet - and if you want to try Electrum, I advise you to read ->
[GUIDE] How to Safely Download and Verify Electrum [Guide]I'm really not sure. I will ask parents during weekend to check again, perhaps there are some hidden files for which I didn't looked for.
Thanks for the link.