The letter of proposed certificate action will cite the justification. During the informal conference, they will lay out on the table what they have, in terms of evidence. That's the purpose of the informal conference. If your guy has something they feel is contrary to what the FAA's attorneys have, they bring it up here. The FAA lawyers don't want to lose in court, so they are usually more than open to anything contrary to their findings. That doesn't mean they will back down though if they feel they have solid evidence. Are you saying all of this didn't happen?

Also, important to note, while a 30 day suspension may be waived under ASRS, it doesn't prevent a violation from going on your record.