Justin's initial reaction was to ask if Ernie'd had a party last night, but rightfully judged the timing to be rather bad for that. Instead, he put his hand on his friend's shoulder and squeezed comfortingly.
"I wouldn't worry about it, mate. You had the nightmare last night, didn't you? You can't control what happens when it upsets you. But if it'll make you feel any better, we can look up some impenetrable and fireproof charms. Anything else and I doubt it'll be any worse than what used to happen before I turned 11. And Mum wasn't kidding about considering you an extra son."
With the reassurance done, however, concern crept in. "So you've been reacting this way every time you've had the dream? I'm so sorry, mate. I should've been with you ever time."