Yes,it’s not difficult to imagine anyone falling that distance having a massive,fatal heart attack or stroke on the way down. And I suspect that that would even be true with a young,healthy person.
The writer should have done his research better.
The GC Skywalk is not part of the Grand Canyon National Park so this death would not show up its statistics. The Skywalk and GC West are owned by the Hualapai Indian tribe and not part of the GCNP.