I think what he wanted/looking for was a easy, fast fix as the "1st step" with the compression of the drive and then possibility of a upgrade later... You being the ADMIN of the server is all that would have taken for the compression, the "user" would have no reason to believe or even know their files were being compressed to save space, in other words their interaction of compression what have not been needed because compression of the files would have happened automatically because of your ADMIN command for them to be compressed when being written to the drive (shared folder).
Easy way to compress... right click over the drive, properties, general tab, check box "compress drive to save disk space".
I am assuming he wanted you to compress the drive, no down down time what so ever, not to remove any so called out dated files... When it comes to a business, no file is "ever" out dated, save, save and save some more.
Above is just my thought, I could be way off, but hell it sounded good to me.