Component makes use of five RCA plugs on the television.
There are 2 different component cables with RCA connectors. One has 5 plugs, red, blue, green for video and a second red and the white for sound.
The other only has three plugs, red, blue and green for video only. You still need a second cable with red and white like the traditional home stereo RCA audio cable to get sound.
He can use the cable he has now as he is hooked it up and unplug the yellow cable. Then run out and buy a 3 plug red, blue and green RCA cable.
So whether he needs a 5 plug cable or a 3 plug cable plus a second cable to plug in for sound is a moot point.
Right now he has sound only with no video using the yellow, red and white RCA cable.
The simple fix for him right now is to go into the television settings menu and change the video selection for the input from component to the three plug RCA yellow, red and white connection or if he already has a red, green and blue cable is to disconnect the yellow plugs and connect that cable. If and only if the device he is hooking up to has component outputs.