I think you could overpot the turn but overbetting the river is bad. Think of what he has. He doesn't have a set, he likely doesn't have 2p unless it's KJhh. Also very unlikely he has a K here, maybe he backed into a pair with Jxhh. So his hand we can conclude is likely very very weak and likely a busted draw with hearts or a lone 6 it sure isn't enough to get value out of a river push. As the above poster said, a river check is good and much better than an overbet.