Isn't he the opposite of a traitor though? Yeonjo explicitly told him to not lie to Hye-ryang the second he starts doubting him. He still tried to lie but ultimately ended up (kinda) listening to Yeonjo.
Don't get me wrong, I despise the guy for all the shit he did in the past but I just can't call him a traitor for telling Hye-ryang.
Yes cause Yeonjo is kinda dumb, he forgave his first abuser way too easily and fell in love with his other abuser, anyways he told this guy to say the truth cause he didn't want to put his life at risk, but everyone should know better that he shouldn't have said Yeonjo is still alive. It ain't so hard to shed some crocodile tears, but Heeryang realised Yeonjo was alive when this guy treated his death as no big deal, and then he couldn't even keep up the lie. He's awful to me, even if Yeonjo said it was okay to tell the truth he should've known it wasn't the right thing to do.

All he had to do is look at the dead body and cry his eyes out, blame Heeryang for Yeonjo's death and say some cursing words to make it more believable, but NO, he had to appeal to Heeryang's humanity and say "well maybe he is alive somewhere far away, don't you think that is for the best for both? If you care for him let him go"... Can't believe Yeonjo trusted his life to that useless man