Cas stayed with Harry for a little while, making sure he was really asleep before he activated the alert ward on Harry’s room. The ward was Ancient Potter Magick and as he was the current Potter Regent, it was tied to him, when Harry awoke or if he got distressed at all he would hear a buzzing in his ear, the pitch and volume of the buzzing would vary depending on the situation. Harry just waking up would be a low, soft, quiet, non-urgent buzzing, if Harry was seriously injured it would be a high, harsh, ear splitting, demanding buzzing. Cas had only learnt about this ward, and that it had been added to his own childhood bedroom, shortly before his parents were killed when he was thirteen and permitted access to the Potter Grimoire. Satisfied that Harry would be fine with the ward monitoring him, Cas went to his own room, so he could work on unpacking a few more of his things and setting up his bedroom. He set an alarm charm for two hours, knowing if Harry napped for more than two hours then he wouldn’t go to bed at his bedtime. Harry usually woke himself up before the two hours, but it was better to be safe than sorry.