Preflop
Standard open and I like to go 3BB when this deep.
Flop
Standard C-bet with top pair, and half pot is fine in a tournament. Since stacks are so deep, you could also go a bit larger, as would be typical in low stakes cash games.
Turn
I really dont like raising his donk bet. When he lead turn, he is representing a hand, that just improved. That means a straight (86 or 63), two pair or maybe a spade draw. Maybe once in a blue moon he could have a hand like 76 as well, which flopped an OESD and turned a pair, and which he is kind of confused about. But in general you only beat his draws here, and whenever that is the case, your hand is not strong enough to bet or raise. You have a bluff catcher, and with a bluff catcher you either call or fold. In this spot given the price and the fact, one more card is still to come, I think, you have a very clear call.
River
Totally happy to let it go check-check.
__________________
|