The company should have plans in place for what to do when something happens to the CEO. Situations like this, death, or just deciding to leave. I've read reports that Nvidia didn't have this, which would be irresponsible if true, but it's not the norm. The founder leaving is likely a bit different than some other CEO coming in later, but any good CEO should be thinking about what happens to the company when they're gone so people know the company is still in good hands.