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It works without email address. Your friend can create his own keys with https://steemworld.org/key-generator and export the required data to create the account from via the "Export Public Keys" button. He first needs to check if that accounts exists already, of course. The exported file will only contain the account name and public keys, so your friend needs to make a copy of his password and/or private keys by himself.

He then sends that file to you and you just import it here:

After the account name and public keys have been imported, you just click on "Create Account". You first need to claim at least one Account Ticket in the section above, of course. This will allow you to create accounts for other people without even knowing their master password or private keys.

 last month 

I guess I will hit some buttons to try it out first before I mess up more. 😐

I assume via steemworld.org it can be figured out if an account name exists?

Yes, just try it out once on your own and create a test account or so. The Account Creator tool will tell you if the account exists when entering the name there. I probably could improve this and add this functionality also in the Key Generator tool. Will think about it...

He needs new email address?

 last month 

If done via steemworld.org an email address isn't needed but his account is made or the name is taken. 🤔
He can't use it again.

Okay. Noted. Thank you very much.