Friendly 1/2 games are tough to judge and you haven’t told us a lot about the villain here. If he were to call is he deep enough to rebuy? Or was this a “I lose and go home” situation. Sometimes, you’ll play tighter in those instances. As previously discussed, he may have a line on your play. That you only 3 bet if you had the dead nuts.
Realistically I don’t see him having 3/6.. This looks way more classic top pair that he knew went bad..