Don't suggest variants like : he will get notification on email. phone etc. I just want to know what would happen in the case when he will never log in into his account.
hmm..
This is pretty much me. I have a +4 year old account with probably around 100 referrals, but I can't access it because I don't know the login (btc address)
And I didn't put the email in when I registered. I even know my ID, would even guess password in a few tries I'm sure, but that doesn't help me much.
I *might* have this info on my old PC, but I just tried turning it on few days ago and BIOS doesn't recognize HDD so windows do not load.
¯\_(ツ)_/¯
You could also try connecting your old Hard drive to a new computer using an usb adapter. I do usually do that to recover old info, and they aren't so expensive