i'm guessing you never do backups?
long story short: no
short story long: the account is easy enough to recreate. if you knew what his ID was before, maybe you could salvage the mail store files from /opt/zimbra/store using some sort of ext undeleted like
extundelete: An ext3 and ext4 file undeletion utility . Ultimately all your structure would be gone though because the folder structure is stored in a db that was deleted too. so the best you could hope for would be to inject whatever emails you could recover straight into his recreated inbox