I wouldn't put a bright mic like a C3000 or Peluso CM6 on a flamenco guitar - too much high end fret noise and finger noise, not enough midrange. Consider a flat response mic like a KEL HM2d or a ADK S7, or for a little more presence, a Heil PR30 dynamic. You would want to get a USB stereo recording interface, so that if he ever gets serious about recording, he can at least do it in stereo. If you do go the cheaper route with a USB mic, get one for voice over work. It won't be as bright, which means the guitar won't sound like fingernails on a blackboard.
"You're either with a native DAW, or you're with the terrorists." G.W. Busch Lite