That point was a mere hypothetical, that IF the way he had played perfectly represented KK and JJ, and was unable to represent any other hand, then the river WOULD be break even because:

JJ has 3 combinations, KK has 6; therefore JJ happens 33% of the time (<40%)
And the JJ bet will cost you 2 while the KK will gain you only 1.

Therefore it would be perfectly even IF this was the case.

What im suggesting is that the other factors in the hand are pushing towards the KK side and a raise.

Any chance of knowing the outcome btw? Sorry to be results oriented lol