1,307. A Sleeping Kohein

202:8 A kohein is not permitted to approach within four cubits (about six feet) of a dead person or a grave. This refers to when the deceased is lying in his final resting place; if he's on the bier that they use to transport him while saying Tzidduk HaDin, even during one of the stops, this isn't considered coming to rest and the kohein need only distance himself four handbreadths (about 14 inches).

202:9 If a kohein is sleeping in a building where there is a dead person so that the ritual impurity can enter, and it's not possible to secure the room in order to block the impurity from reaching him, then we must wake the kohein and remove him from the building. If he's sleeping without any night clothes, he should not be told about the deceased. Instead, he should just be told to leave without explanation so that he will get dressed first. This is done out of kavod habriyos - treating people respectfully. In any event, once he learns of the ritual impurity, he is not permitted to remain there long enough dress himself; he must exit immediately.