He will need a card for SAB. When we were there last August, we had to show a KTTW for each family member entering SAB- my sister had to run all the way back to the villas to get her kids cards.
He will also need a KTTW for EMH nights, the cards are scanned before a bracelet is given.
My sister doesn't trust her kids with a KTTW so she keeps them in the safe in the room when not needed, and when needed, she holds them. I keep all of out KTTW cards together in my camera bag.