No, this isn’t a reference to his mental stability, or serious lack thereof, but rather the growing speculation that he is probably quite ill. Analysts say that his decision to make the moves to designate Kim Jong Un as his successor may be a sign that he is quite near death.
Under normal circumstances the death of a crazy monster like Kim Jong Il would be only of mild interest as to just which circle of Hell he is destined to inhabit and how the reunion with his dad would go.
But with North Korea being a nuclear power things are on a whole new level. Kim Jong Un is believed to be in his mid to late 20’s so it’s basically like one of the High School Musical kids taking over for President Obama.
This would obviously mean some sort of regency and a good deal of instability, not a good thing with an already unstable nuclear power.
While it is probably tough for the country to become more hard line, the idea of increased power in the hands of an aging military leadership does not fill you with confidence.