I would have your friend bring some gear and they can fish any time you are sailing. It will be hit and miss and they'll probably only catch fish a day or two.
If you want to help them, you could sail along the South Drop (just sail south from Norman and then over to Cooper on the south side of Norman and Peter).
Be prepared to be able to STOP on command. You can heave-to.
On our last trip we caught a beautiful mahi-mahi and we caught a lot of barracuda which were a real pain to get off the hook.
I wrote a couple of posts on it:
http://bvibound.com/can-fish-sailboat-bvi/http://bvibound.com/gear-take-fishing-british-virgin-islands/Stormy
