for the non-formal or casual nights onboard, dockers and a polo shirt are just fine for your husband.
Last I heard about the adult drink card, they were dis-continued, although that too may of changed, you can see when you get onboard. Some people will pack some bottles of alchol in their checked luggage, you can try that.
In Cozumel you can take a cab over to "Chankanaab Park" for some good snorkeling, very easy to do on your own. YOu may also want to do an excursion to snorkel with the Sting Rays in Grand Cayman. YOu can book with an independent tour guide or through the ship, but be sure to do that one.
There is an imformative thread using this link about the park and whats all there:
Just scroll down a few posts and you'll find it.
We're on Voyager in Feb, doing an exocit Western itinary, can't wait. Be sure to post on how your cruise went when you return, have fun.
Any more questions, feel free to post again.........