Al lowered his wand when Jamie did, but didn't lower his guard. His father wasnt the only one who knew wandless magic, after all. He was the one who had taught them. There might always be a situation where you can't get to your wand, after all.
Then he was apologizing to Al for his name, and telling him the actual Albus and Severus were here, and it was so absolutely, painfully absurd thing that had ever happened to him in his entire life.
He chuckled once, hand flying up to cover his mouth. But it didn't stop, and seconds later he was doubled over clutching his stomach and practically howling with mirth. He didn't think he'd laughed like this in over a decade. It was just so hysterically funny, and Al wasn't usually a hysterical kind of person.
"This, is, either," he wheezed between gasps of unhinged laughter, "the world's, worst, prank, or, or, we, died on the, way, to the, party."