If you are staying on French side, There is a reggae place at Cul de Sac called Stoshi busy on Friday nights. Not sure if that is correct spelling. It on the left just before the pharmacy. Gets busy at about 10-11, but the music should start about 9. Try their fresh fish it's delicious! Calamos in Grand Case on Thursday night, Lagoonies on Fri/Sat nights.
If he is looking to meet girls try Dutch side, French girls aren't interested in Americans.