He said it himself. Inaction is the end of him.

[ ... ]

I'm not actually happy to know no one talked him out of what happened to him. It was something that was weighing on him, that was abundantly apparent even to me. No one picking up on it where he's from is... a strange thought.

[ MAYBE he could understand lae'zel and himself not realising. but karlach? not seeing a friend struggling? it's hard to believe. ]