No, I think Kim is down for the count politically. That's not a country you can run without a strong, paranoid mastermind at the helm. If he's in no position to rule mercilessly, he'll find a new order, or competing orders, will arise below him, and he'll be powerless to stop them. They may even act in his name, and what's he going to do? Drool harder into his cup? Flail in his hospital bed?
I'm not seeing it. If he's even mildly incapacitated, the mice will play while the cat's away. They'll keep playing until this cat gets better, or a new one takes over. But by then, they might not want to stop playing at all.
Now that his life is not far from end, it is now he who is racing against clock, not his adversaries. The whole game has changed. Besides, as you said, he also watch over his shoulder to make sure his minions are not poking him with long knives.