Odds are really good he'll die of a heart attack while in office, but unfortunately that means Vance becomes President and that's honestly even scarier than Trump. Vance couldn't have won by himself, but the amount of damage he could do when handed the presidency is staggering.
He'll be completely under the control of Thiel, Musk &co. That's likely been their endgame all along. That's still plenty bad but at least they won't start a nuclear war out of sheer idiocy.