Hyperbole aside do you know anything about Asia?
I live in Japan and what you said makes as much sense as having Canada take over the US and Mexico because they've been fucking up too much and can't play nicely together.
Personally, I think it would be better to let the North Koreans starve but since the Cold War ended, along with Soviet help, North Korea has been rattling its saber and getting food aide. Trump's the first person to say no which puts both Koreas in a bind. If the South hadn't impeached their previous president there's a strong likelihood she'd have gone along with Trump but the people elected someone who was very public about bringing the two Koreas together. The North is in an awkward position because they know they can't win but they can't back down. And so the people in South Korea want to feed their neighbors and families in the North. That might end up being the band-aid for the moment.
China isn't being shady. Chinese culture and political philosophy are 180 degrees different from the West. They seek cooperation, especially as a country full of potential refugees sits on their doorstep.
And Japan wants no part of Korea. The problems between N/S Korea and Japan started when Japan invaded the peninsula in the late 1800's, killed the royal family and declared it (and eventually Manchuria) a territory of Japan. All of North Korea's hostility towards Japan, with their rockets overhead flybys, can be traced back to those imperial times.