Deleting of the account does not delete the posts, but the new account he creates would not retain his old posts... which I think is what he's after.
And bottom line is, we don't grant these "favors" because it creates confusion and overhead.
And you can "delete your account", but it must be approved by an admin and we currently are not approving them for the above reasons. People can reinvent themselves and provide a false identity to those that would have previously steered clear of said person.