Motorcycle suggestions? Lightweight for an elderly man..?

Though death befalls all men alike, it can be lighter than a feather or heavier than Mount Tai. I told my friend that soon he, too, would be too feeble to ride anything else, and he would be reduced to riding a Harley Davidson. He thumbed his nose at fate, and bought a 250 Ninja. Another season, perhaps two, of real motorcycle riding. Then the inevitable Harley, then...death.