Frederic tells us he and Zsa Zsa's adopted son, Oliver Prinz von Anhalt, died Sunday in a hospital following a motorcycle accident on Mulholland Drive.
That accident occurred the same day Zsa Zsa had a fatal heart attack. Oliver's motorcycle collided with a car.
We're told Oliver was in a coma and never came out.
Frederic says he wasn't aware his son had even been hurt, and was just called by the coroner Monday night. Von Anhalt tells us he thought his son was in Germany and had no idea there was an accident.