607 should be fully HDCP compliant. Try a different HDMI cable.
I know on my 605, there is no "Through" setting to "tell" the receiver to pass video through to a display -- the Edge processor in the 600 series automatically sends whatever it gets through HDMI IN to the HDMI OUT. This must be how the 607 works as well. The only thing I can think of is he should check that HDMI MONITOR is set to YES in the SETUP menu.I agree try a different cable and make sure the Onkyo is set to "Through" for HDMI.