I feel like there should be a noticeboard where you can post "I'm worried about a suicidal guy from Indonesia" so that other people taking calls can pick up and explain to him what happened. Perhaps/ probably you are not encouraged to hold onto such stuff but in the old old days when I used crisis lines I would have been grateful that somebody knew about me and explained.

That's all you can do. Mistakes happen, and thank goodness you are not responsible for him living or dying. You are not a train driver making a mistake, just a person opening up on a crisis line and doing their best to be helpful.