A malignant brain tumor is tragic and nearly always fatal. Ted Kennedy Diagnosed With Malignant Brain Tumor [ABC News]. The fact that it has happened to Jack and Bobby Kennedy’s younger (and only surviving) brother, a legendary Senate legislator — with close friends among Republicans and Democrats — and to a Kennedy family that has seen more than its share of tragedies over the decades, is just plain sad. If this were not reality, I would say it’s time to call in Dr. Gregory House.