The author, alas, only sees two possibilities. Either allying with North Korea (backing the regime) or "real pressure" much sounding like a call for stricter sanctions.

Economic assistance and humanitarian aid is not necessarily backing the regime though, at least not more than sanctions. The past decades have shown that stronger sanctions do not weaken the regime very much (looks like Cuba again, or Iran today). During the North Korean famine about 5-10% of the population died, but the regime did not change much. So when the author is saying things like "the North Korean REGIME can sustain itself only with Chinese backing" or "[China] could afford to allow its erstwhile ally to implode" the author asserts that the North Korean regime would suffer under sanctions or other constrains (and not just the North Korean people).

I mean the point that China should reconsider its relationship with North Korea is right, but thinking that the North Korean regime will implode through a tougher stand is at best a lack of clarification and at worst a tremendously short-sighted view, that might be compromising the author's lack of knowledge of empirical data about the impact of sanctions.