That could be a tough thing for your family member to have to deal with. Hopefully Cox will restore their email, but I've never heard of them doing that for anyone. If they do it for you, you may have to sign an NDA. 😩
I read a lot of information from Cox websites and today was the first time I became aware that Cox had an expiration period on messages in any folder other than Trash and Spam. This documentation says that unread email in Inbox will be deleted after 60 days. Had none of the lost email in Inbox been read? As long as a person doesn't exceed their Webmail storage limit, this policy only seems to benefit Cox by reducing storage space used by customer email.
You may not be able to recover lost email, but you can prevent it from happening again. The documentation says: A message may be retained by downloading it via a POP-3 client (such as Outlook Express), moving it to an alternative folder in WebMail, or by marking it as "Read."
- Create a personal Webmail folder, e.g. MyInbox.
- Create a Filter Rule with Action: File into and Select folder MyInbox
This will copy all incoming messages to MyInbox that are going to Inbox. This will create two copies of incoming email, but it will prevent unread email in Inbox from being deleted again.