What parent means is that it's still random, as that person could just as well have lived 121 or 123 or 125 years.

But that's a trivial observation that doesn't really change anything. 122 wasn't never supposed to be "non-random" as in some kind of physical law. The natural law concerns the increased certainty of death observed as ages > 100 approach, not a hard and fixed 122 number encoded in our DNA.