A couple of options: (I am coming to this from a on-premise point of view)
Weblink can still your friend here, you can have an internal only weblink that is inside your firewall. Then create a 'public - internal' user to provide access to that without having to have a license applied. I have this in use here in my system 2 weblinks sites, one public facing, one internal access only.
Have a passcode, known to him, form that retrieves the previous archived documents from the repository, this could be created to retrieve and show, or retrieve and email documents found.
Machine License, you can have a machine license applied to a station that provides a user, from a user group, access to the repository from that one machine and your user would use their LFDS credentials (AD in my case). That would then allow you to use group memberships/tags/etc., to limit repository reach but have a station where a user can work/view the repository, multiple users that do not have licenses can be given attributes to specific areas of the repository. I also have this running here.
Options......
r