I say mic the guitar no matter what. Unless he has a custom-installed pickup system that has both a pickup AND a mic, it's not going to sound very good.
If sightlines are a problem, I'd go for a
Countryman ISOMAX 2 with the appropriate clip. Move the mic around until you get the desired tone.
If he does have a nice pickup/mic system installed, you'll probably need one or two DI boxes to interface properly. Make them active, as the input impedance should be nice and high to keep the tone of the guitar accurate from the pickup.
Wolf
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