There is nothing wrong letting him "do his own thing" but there are times when you need to do things as a family also --For me personally i would be a little leary of leaving a 15 almost 16yr old alone on the ship while you were off in port, what if something happened to him while you were off exploring an island, or visa -versa?? I am sure you could find an excursion that would be fun, interesting and a new experience, and if he makes some new friends you could all go as a group on a tour. I think that you must have some way to communicate with eachother while on the island - 2 way radios with a 5 mile radius might be your answer. I have a 17 yr old son, so i know exactly what you are going through. Another thought- could he bring a friend to cruise with? I know its short notice for you but it could make things easier on you and dear J.