DPRK are openly lunatics.
Sad but true. The people of North Korea has been suffering in poverty and that's likely to continue. China want to keep it as a buffer state at all cost. China has also benefited from all the sanctions since NoKor have no one else to export their minerals but - you guessed it - BFF China.
China will counter any attempt by the US to get rid of the regime in NoKor. A government sympathetic to the US would be the last thing they'll want at their borders. Seems the only way to lift up the North Korean's would be if it's China that will force their government to change. Hopefully even the Chinese has gone tired of a neighbor always threatening nuclear war.