24 hours and counting. Tomorrow is Clay's birthday party.
I asked Clay's mom, and they do have a dog - a small one, who will be kept away from the party. I talked about it with Bud and let him make the call. He insists that he wants to go, and says "The doggie is barking me. She's won't nearing me." This is my cue to reassure him that, in fact, the dog will not come near him.
I've never spoken to Clay's mom about Bud's autism, but of course in many ways it speaks for itself. I did tell her about his fear of dogs. "Even if you can only stay for 15 minutes," she said, "it would be great to have Bud there."
That was the right answer.