Usually it requires a solid second in command to step up and reform things to save it.

And like most petty dictators, Trump has been diligent in preventing anyone from becoming a solid second-in-command, because he fears all potential threats to his dominance. If he dies, because he’s an out-and-out monarchist, the only possible heirs will literally be his heirs, and fighting between his children to assume his legacy will be bitter and bloody.