I know a guy who got himself hospitalized, because he kissed his girlfriend - who had a Snickers before. Whenever there was a risk of peanuts in the room, he warned everyone, that if he were to get red in the face, an ambulance was to be called immediately.
This works if your an adult. At a younger age, it is quasi-impossible to prevent children from ingesting poisons. By reducing the amount of poison in the environment, chances are higher that they will reach maturity. Home-schooling is not always a practicable solution.
Not to mention, that PB&J isn't healthy even for most of the non-allergic children.
But this is such a classically American response, that it is quite entertaining to follow. One should never give up luxury, even if another's life is at risk. Institutionalized egoism still going strong.
FYI his reactions was likely psychosomatic, because people cannot go into shock by what you described.