He's provided for each of them the opportunity to lead a life of health, wealth, and power far beyond their imagination. By his own example, he's shown them that such gifts are meant to be shared, used to make the world a better place. And he's never asked them for anything in return, showing a willingness to risk even his own life to live to his own ideals.
Now Will Stark needs their help. He's helpless, he's uneducated, and he's about to meet men who can utterly destroy him.
And they'll need to make sure that's exactly what happens.
Prodded by memories and with the aid of future hindsight, they'll work tirelessly, take on alternate personalities, and ensure that the plan is carried out in its entirety. In the process, they'll learn that selfless sacrifice can demand a heavy price. They'll know that even high technology can't overcome the human spirit.
And they'll understand that, even with perfect hindsight, surprises beyond expectation can—and do—occur.