It's definitely not the prime time to tarpon fish in the keys right now. The main large fish migration occurs in the spring, but there are always smaller resident fish (10-50lb) that reside inshore. If he is interested in that, any reputable guide should be able to make it happen. As for sailfish, it really depends on what part of the keys he is in. Middle and lower keys sailfishing doesn't heat up until later in the winter/early spring, but they are still worth pursuing. Reef fishing should be pretty good right now. Kings and wahoo are on the reef line and the grouper have moved in shallow. As for flats fishing, there are large cudas all over the flats in winter and they are a blast on light tackle. Bonefish and cobia are definitely not out of the question either.