There are many things that might have caused the delay. If he has no minutes left on the card, if there was some sort of group punishment where the phone use was restricted, or he could have lost his phone privileges. Being in jail is not like he's staying at a hotel. He is told when to go to sleep, when to wake up, when to eat, when to go to rec, when to shower and on and on. You will have to cut him some slack because it's impossible to know the full truth from the outside or to fully know what is going on inside his head. He is dealing with a different set of priorities now and trying to adjust to his new surroundings is not easy.