I doubt there will be anything serious in it.
He has to balance his employability in future with the amount he's paid for the interview, and he's not so daft as to do a hatchet job on H&M whilst leaving W&K unscathed (however one sided the truth likely is, I wouldn't buy that W&K were whiter than white).
I imagine what he says will be either anodyne or obvious.
For example, "oh, believe it or not, the fact his father and wife both had cancer really got him down".