i think the 18 words long phrase that you have is also a Seed meaning you can use it to recover your private keys. but the setup before that was different it had 20 words and it was not a Seed and it could only be used to recover the "password" instead which is why it was called "Wallet Recovery Phrase" instead of simply "seed" or "mnemonic"
'it was not a Seed and it could only be used to recover the "password" instead which is why it was called "Wallet Recovery Phrase"'I think you got it mixed-up, unless I misread or misunderstood that part of your sentence
my "18 word" is not a seed and called a "Wallet Recovery
Mnemonic" (not phrase) by bc.info, for recovering password
they used the word
Mnemonic for password reminder, not for seeding wallet as common use now
here's what I've written down exactly as shown when I created my wallet (Legacy Wallet)
Wallet Recovery Mnemonic
Your wallet has been created successfully. If you forget the details the phrase below can be used to recover everything.
Please Write Down the Following:
*** *** ***
Do not save the mnemonic on your PC or in your email drafts! Write it down or print it!
Without the mnemonic we cannot help recover forgotten passwords and will result in LOSS of ALL of your bitcoins!.
The current one is called "12 word recovery phrase" and it works as wallet seed to recover HD wallet private keys
currently they can send email reminder of lost Wallet ID but they can't recover your password
and the only way to recover your wallet is by using the 12 word phrase and the system won't accept more/less words
bc.info started to use this "12 word recovery phrase" in 2016,
since then all legacy wallets are automatically upgraded/converted to HD wallets
that's why I believe if he has "12 word recovery
seed" and done this in 2011, it couldn't be bc.info
it's either he remembers the words length incorrectly or he didn't sign up on blockchain.info
easy way, he should try entering his email in the wallet id reminder,
if bc.info acknowledges and processes the request, then he has an account on blockchain.info