If you have position on a blind, I bet-fold the turn ui and hope to check behind ui on the river. Not having position (CO vs btn in your post) is trickier, but against an opponent like that, I'll bet the turn and c-f the river. If he's that passive, he'll often check behind on the river even with an Ace because he's worried that his weak ace is weaker than my weak ace. Also, often as not, he has some other piece of the board and will fear our weak ace.