Unfortunately he's as clueless as you on that topic. For those who don't know, the Phanerozoic eon spans from the Cambrian onward, during which time multicellular life on earth has proliferated.

U/Pb dating of zircon
TEMORA 1: a new zircon standard for Phanerozoic U–Pb geochronology

Pb dating of zircon
Precise determination of Phanerozoic zircon Pb/Pb age

And a good detailed article about how the geologic column is dated. Of particular interest are 15.10 Dating sedimentary rocks, and 15.11 The geological timescale. Here you can read about the various ways that scientists date layers. Of course, Woodmorappe has omitted what is IMO the most obvious one: you can have igneous layers below and above sedimentary deposits. Radiometric dates for those will give you boundaries for the age of the sedimentary layers.

Given his qualifications, I wonder why Woodmorappe doesn't mention these things, as he must be aware of them. Strange, don't you think?

You also have not addressed the heart of his argument, mentioned in my post above. If you think you can lend some logic to it then you are welcome to try.