He died this September. The obit doesn't give any cause, but apparently as recently as 9 years ago he was trying to lay hands on radioactive material--americium from stolen smoke detectors. The obit didn't say whether he died of cancer.
He had his problems (pretty severe, if getting charged with theft for tiny quantities of americium is any indicator), but he dreamed big. A home-made reactor: that's deadly crazy. But cool.