I bet the wife made lunch and the father made some stupid comment about it. That's why he looks like a deer in headlights, the wife is giving him the look, and the son is thinking to himself, "Now you've done it!"
Very nicely done shot! I think the kid is asking, "Do we know that guy taking our picture?" Then you have the guys in Elizabethan garb looking over the top of the wall in the back...