Quote Originally Posted by Craft (Cheese) View Post
I just didn't have the heart to kill his character right there, so I had the goblin just get bored and walk away.
Well, there's the problem right there. He has no penalty for ignoring mechanics. You have justified his decision to roleplay everything by removing all mechanical penalties for his actions. When you start applying consequences for his actions, he will take actions which avoid undesired consequences.

If you didn't want the goblin to kill him, then you could have had the goblin tie him up and drag him back to the goblin camp, where the whole tribe gathered around an altar and a cookfire, preparing to sacrifice him... and an old woman, also recently captured. Now, your player must rise above his own inadequacies and traumas to save someone else's mother. With violence!

Yay violence!

I would also second the suggestions to play a game whose mechanics better support roleplaying. Looks like you're already going down that path, so pretend I traveled back in time to say this before you made that decision.