Because he didn't have billions and prefers that his money is spent on a future for his three children. His cancer was rare, so he donated his body to science,

Because he didn't have billions and prefers that his money is spent on a future for his three children. His cancer was rare, so he donated his body to science, in the hope it might save people from what he had to endure. (In private he told me it also saves the costs of a funeral. That's Pieter for you ;-)