Why would that make any difference? China and NoKo aren't kissin' cousins. Oh, b/c China has a bigger army? That doesn't seem to bother NoKo one bit.
Remember, it wasn't that long ago that China was sending them train loads of food, and the NoKos were keeping it(them) -- the food and the trains! China barked at them that they wanted their *&^$! trains back...or else. Kim & Co. essentially brush them off with an airy wave of the hand. China ranted and raved a bit more, then pretty much let the whole matter drop.
IOW, China vis-a-vis NoKo is no silver bullet.
True, and North Korea has nukes and someone crazy enough to use them at the slightest provocation.
Chances are the best bet would to be wait it out until he drops dead. Which might not be very long if he has already named his successor.