The Democrats have quite a problem to solve. Ideally, Biden would step down voluntarily; but that would require a degree of humility and self-sacrifice seldom seen in our upper strata of politics. They could provide a portfolio of financial goodies and prestige jobs to the Biden family by way of incentive, but would need to rely on a fickle media to cover it up or dismiss it as normal practice.
They could try a 25A strategy, or some sort of jiggery-pokery at the convention, but that would be chaotic and embarrassing. And all this will take the focus off Trump and on their own internal struggles, which frustrates their best path to victory.