~NL25. Losing value with KK?

[Dalek]

As both 5 and 6 are nearly all of the villains total stack, there is little psychological difference. Just put him all-in.

If you feel he has a busted draw and won't call a bet then you should check-call or check-raise. In this situation (low limits, seemingly passive player) it is much more profitable to bet and hope they will call with a worse hand which is probable.