I have just come back from a short break in Jersey.
The zoo is excellent, quite small but plenty to see, make sure you see the gorillas!
St Brelade's bay is lovely, with some great places to eat on the seafront.
The cliff walks around Bonne Nuit bay on the north coast of the island are wonderful, tranquil and peaceful.
Shopping in St Helier can be cheap due to no VAT on most purchases.
Oh, and if they are taking a car over, be sure to fill up as petrol was 77p / litre 2 weeks ago!
Hope they have a great trip.