I'm actually starting to think that OP just likes to try to use big fancy sounding words, but often accidentally uses the wrong one.
Here, I think he meant to use the word corroborate.
Last year, when he said he was mortified, I think he meant to use the word horrified.
In both instances, a rhyming/similar sounding word fits perfectly in place of the other word.
I'm no OP defender :truce:, and I believe he murdered Reeva in a drawn out, purple-faced, mother-of-all-temper-tantrum rage, but when it comes to these word choice oddities, IMO, he's just trying to sound linguistically advanced....and failing.