1. You need to first be able to access the drive to know what exactly is in there. You could be having some Bitcoins or nothing at all. This means you may have to get in touch with a professional HDD data recovery specialist if the headers are messed up due to the drop, which can also be a complete gamble.
2. Once in, You need to establish if there was any address in which the BTC may have been kept or not. Or if he stored the private keys anywhere in the drive. Also, he may need to recall any passwords he may have used at that time in case there is any encrypted wallet file that need sot be accessed
but could the miners have got what he wanted when i hooked the drive up again briefly, ive like and idiot opened it and tried to fix it......
Nah, that's not what miners do and that's not how the network works
Maybe you just have to be careful with any hacker if they land on your private keys and passwords. Both should never be anywhere on the internet or device that connects to the internet such as cloud service, Gmail, notepads etc.
but reconnecting it to the internet could it prove to miners that we mined on it? and maybe recover, i say we as bitcoins in the year before that were worth nothing and maybe an obscene amount, including other sorts of crypto, worth nothing back then..
if you managed to gain access to your wallet.dat file or private key, that all that matters mostly. You could get your wallet synced to the blockchain to reflect the actual balance on the wallet or import the private keys into another light wallet such as electrum.
Bottom line, you would see your coins and be able to spend them if they were actually in the address. No one can touch them unless they gain access to the credentials or private keys.