Hi everyone.

I need your help. My friend died in a car accident a month ago. Before that, he traded cryptocurrencies a lot. His wife asked if I can help to restore access to his wallets and withdraw all funds. So she gave me a flash drive. I found private keys for eth, xem, and other currencies. But there was also a file called 'wallet.dat' on his computer, but I don't know for what exactly it is. I have never encountered with bitcoin and other cryptocurrencies before, but I have some experience in IT, so I tried to help her.

I googled and found that this file contains private keys and other info, so I need to import this into a wallet and that's it. But I don't even know if it is bitcoin or litecoin or etc. I tried electrum, but it says "Cannot load wallet: 'utf-8' codec can't decode byte 0xe8 in position 52: invalid continuation byte". I've also tried bitcoin-qt, but it also fails:"wallet.dat corrupt, salvage failed".

Also I found a python script called pywallet.py(https://github.com/jackjack-jj/pywallet) and tried to run it, but it throws an exception:
bsddb.db.DBInvalidArgError: (22, 'Invalid argument -- BDB1009 ./wallet.dat: unsupported btree version: 10')

`file wallet.dat` returns "wallet.dat: Berkeley DB (Btree, version 10, native byte-order)"

I don't know what I can do with this file. Is it corrupted? Or I am trying to import it in a wrong way? I really appreciate any help you can provide.