Yes, I am always checking in with my friends about how their kids act and YES, 99% of kids panic when they think that vomit is a possibility. The KEY is whether or not he acts normal the rest of the time. Emetophobic kids disturb the normal function of life with questions about vomit and are constantly looking for reassurances that they aren't ill (like many do here). His reaction wasn't out of the ordinary if his tummy was wobbly. It would be concerning if he were doing this every night, not just now and then.