Certainly China is about the only country with any clout in North Korea. I suspect that they don't want a lot of sabre rattling on their doorstep but are probably not massively worried about it at the moment although I think they watch the North South Korea spats very carefully.
If the food parcels, medicines, educational materials, any good things were part of a saturation bombing exercise of some sort (not actual bombing) then with sufficient momentum, it couldn't be stopped. The same thing might work in Iran. Of course, it won't happen in either place.