No worries. At least he agrees to wear a jacket.
On my last cruise, there were teens with jeans and t-shirts on formal nights but they weren't allowed into the dining rooms for dinner until they at least had an appropriate shirt on.
Mariner-05/06 & 10/09
Oasis Inaugural Cruise-12/09
Monarch-03/10 & 07/10
Mariner; RSS- 10/12
Independence of the Seas; 12/07/13; Booked
Enchantment of the Seas; 01/24/14; Booked
Legend of the Seas; 04/16/2014; Booked