I need helppp :(

The unavailable message usually means that a used Apple ID doesn't match the one the App Store recognises.
Have you access to another Mac you can make a USB installer from?

 

You aren't so lucky as to live somewhere close to an Apple Store, are you? I'm sure they could get an OS on it for free and without hassle. If not, and you can't get a hold of another Mac, the only solution I can think of is not a very good one - trying to find a download for an OS X/macOS installer on the internet. Since it's not from Apple I don't like that approach, but you could, if you can find one, make a bootable USB with it through Linux or Windows.

 

You can do a net install. It's cmd+option+r I think during boot up. I would recommend connecting the computer via Ethernet cable. If you want to make any attempt at data recovery on your hard drive you should do so BEFORE doing anything else.

 

I was under the impression that was what he had tried to do before.

 

Yes. That should work