A guy I work with (I wish it was me lol

) bought btc back in early 2013.
- He has an email with an attachment (assuming wallet back up)
- He has an email with the 12 words
- He has an email with a wallet id number
I'm guessing he has to downlaod bitcoin core, and then he can open the attachment, get his btc, and be

I could be talking out of my ass though, so any thoughts on if this is the way to go about this, or not.
Thanks.
The 12 words should be a seed. Since it has id number and that attachment (maybe named "wallet.json"), it could be a blockchain.info wallet. It is easy to recover using another wallet where you can import your wallet.json file (blockchain.info old backup file).
As a side note, I'd say it is very risky to keep important infos about your Bitcoins on your email. If someone hacks your email, he could easily steal your funds...