Betting into the nuts

Harpit Gurnham on the big blind calls a minimum raise from Marcus Farthing on the button. His K J matches the Q T 9 flop very nicely and he check calls 7,000 then 6,000 bets on the flop and turn. The 6 7 means he still has the nuts on the river but Marcus just checks behind this time aware he’s not going to get called by anything which isn’t beating his A T