Kaito never had a curfew, mainly because his parents were often too busy to oversee his bedtime. Whenever he was on tour with his dad, he would usually go back to the hotel room straight after the show (that he would stay up to watch, obviously). Usually, he would be asleep by the time Chikage or Toichi would come in to check on him, but sometimes he wouldn’t be able to sleep and they would read him a story to lull him to dreamland.
(Chikage, ever the prankster, would read him Arsene Lupin. Toichi, who had more common sense, would read him Le Petit Prince.)
When he wasn’t on tour, Chikage would stay at home with him and read him stories and make him hot chocolate before going to sleep.
A little bit after Toichi’s death, Kaito stopped sleeping properly. Chikage was never around to comfort him, and Jii-san, as good of a caretaker as he was, was also in mourning. Kaito was often left alone, so whenever he got too upset, he would make himself a cup of hot chocolate and read himself Le Petit Prince.