Well, they haven't even begun to look at civil suits yet.
Yup, civil suits, particularly following the Fastow's admission of guilt, will easily bankrupt their family, if only in the costs of defending those suits. Meanwhile, the real action will come when Fastow starts testifying against his higher-ups. They're talking about charging Causey "soon", and then it's probably game over for Skilling and Lay.
Also, if you read the articles carefully, the Fastows have only plead guity to a small number of charges, but they haven't been let off the hook on others. That means that, if Fastow doesn't testify to the satisfaction of the prosecution, they can bring the other charges back on the table. According to the NY Times article, this may become a chief weapon of the defense, claiming that Fastow is making things up in the name of "cooperation" with the prosecution.
Ultimately, if they nail Skilling and Lay (and the Tyco president, Kozlowski), that might actually scare other executives into getting their act together.