He is either booting into the Yosemite RecoveryHD, since that hasn't been replaced yet by the Installer, or launched the Yosemite installer instead of the El Capitan installer.
@tdatsmrad,
In case you have a "/.IABootFiles" folder, then remove that and launch the Install OS X El Capitan.app.
In case you have a "/OS X Install Data" folder, then remove that and launch the Install OS X El Capitan.app.
Note: You have to replace ./IABootFiles/boot.efi with boot.efi v3.0 before it restarts, or from your Yosemite drive, before you can continue with the installation.