I think he just misread the viability of programming a Boomer-centric format and not including enough music that also appeals to younger demos.
The sad part is he put his reputation on the line, and authored numerous articles promoting the commercial viability of formats aiming at 65+. The station airing the format apparently didn't find any benefits in that demo, and asked him to adjust the music. That's what led to the ratings drop.
But I've said this numerous times that the easiest way for any radio station to improve it's 6+ share is to add 60s music to their format.