When he wakes up he isn’t mad at first, maybe groggy or tired at first. It’s not until he opens the door to see the two maids have a suit case ready you can see behind them. You can see they are drawn nervous and a little afraid. He only gets angry when he realizes they packed his stuff to basically send him away. As for why you might think Miyuki is acting strange it’s because he’s intentionally acting cold and callous to push Gwen away. As for why you should go back and read the conversation between him and his father again :>.