The best rule of thumb is to never send files to people if you want to ever see the bitcoins again.
When helping others with key recovery my rule of thumb has been to write a program (with available source code) that they can run on their own machine to perform any recovery/bruteforce work necessary. I can try to take a look at this from my end though. Also, @OP: Check the trust rating of members before sending money or sensitive files to them, and don't send such things if you can avoid it. Much easier when you can get a trustworthy program with source code that you can run locally to perform the recovery.
However, if any of the files contain numbers that look like L1fdK2N... (starting with K or L) or 5JpikxbM... (starting with 5), then you are all set. Those are your private keys, which you can import into any wallet.
mbhd.wallet.aes would be useful if you stored your coins in the Multibit HD wallet. It's encrypted, so you should see if you might be able to remember the password to it. If it's a ZIP file, look inside. It should contain folders called mbhd-[some long number]. See
https://multibit.org/help/hd0.2/restore-wallet.html for more details, reply here (or by PM) if you need more help.
