My friend lost the password to his email account.
He tried to reset it about a year ago, but couldn’t, because the phone number linked to the email doesn’t exist anymore.
Web.de support couldn’t help either. If he tries to reset the password now, it says that the email no longer exists.

Now the obvious problem:
He can’t log into Steam anymore, and he doesn’t show up in our friends list.
I also didn’t find anything useful in Steam Support regarding this situation.

Question:
He still has old PayPal receipts and transaction IDs that clearly belong to his Steam account.
Is that enough for Steam Support to recover the account, even if the email no longer exists?
Or is the account lost once the original email is gone?