Your son will surely look dapper onboard with his tuxedo on, Tracy!
I love the fact that he has his own tuxedo -- you must definitely plan to bring it, since there will be a formal night on your voyage. Your pictures will be so awesome -- make sure that you take family and solo photos in the evening at the lobby atrium on formal night. The professional photographers will usually setup their signature Disney Cruise Line backgrounds and these make lovely mementos of your voyage.
Remember to check the Personal Navigator once you are onboard. This daily newsletter of events and activities will provide you a reminder of the dining attire suggested for each evening. If you have a smart phone, you can also download the
Disney Cruise Line Navigator App now -- you will need to refresh it once onboard and the data will populate. You'll have all the information at your fingertips, and using this App onboard is also free. On formal night, you'll notice that the Disney characters will be out with their best formal attire too -- your little gentleman will need to have a formal photo with Captain Mickey and his gang. I'm sure all the Disney Princesses will want a photo with him too... so keep your camera handy, Tracy!
Have a great day!
~Dolly