In practically every measurable parameter, those who exercise enjoy better health than those who do not. There is accumulating evidence, however, that at the extreme end, like frequent marathoners or iron distance triathletes, the benefit curve starts to drop off and more is worse. There does seem to be an increased risk of atrial fibrillation in that population.
It is just as possible that without the cycling, your friend would have died at 59 instead of 69. One can never measure added years in a single individual, but it shows up in large populations.