Dude you don't get to argue "they don't have to" when you just said "a big chunk of China" would get nuked. You're either making the point that China is in danger or you're not. You don't get to spasm out maladroit dudgeon to see what lands.
Though, if that certain somebody gave the order to launch nukes, and nobody listened to him, I don't know what would happen next.
Nothing. Nothing would happen.
Moreover, Defense Secretary James Schlesinger recalled years later that in the final days of the Nixon presidency he had issued an unprecedented set of orders: If the president gave any nuclear launch order, military commanders should check with either him or Secretary of State Henry Kissinger before executing them. Schlesinger feared that the president, who seemed depressed and was drinking heavily, might order Armageddon. Nixon himself had stoked official fears during a meeting with congressmen during which he reportedly said, “I can go in my office and pick up a telephone, and in 25 minutes, millions of people will be dead.” Senator Alan Cranston had phoned Schlesinger, warning about “the need for keeping a berserk president from plunging us into a holocaust.”
I think the further you are from the nitty-gritty of nukes the more determinist you are - there's this idea that the dude in the Oval Office says "cry havoc and unleash the dogs of war" and everyone on down the line goes "whelp, I guess that's it! Nice knowing you, honey, see you in Thunderdome" and we all start singing "Christmas at Ground Zero." There's a whole lot of people between order and execution and not a one of them was a bored real estate developer two years ago.