It isn't about the external world though. You could live in an utopia, experience grief and loss, and be unable to feel happy or do the things you want to do for your whole life because of it.
Regardless of the condition of the world, you would suffer. Suffering is an internal, mental state.
I think it is best to try to reduce that suffering as an end in itself. But you could also think about it in terms of helping the suffering person achieve whatever it is that they want. No matter what it is they want to do, letting go of their attachment to their suffering will be beneficial. That includes changing the material conditions that caused the event in the first place. It is easier to do that if you aren't suffering.
Also, that is not to say they just "forget" and move on. It is simply that their relationship to the event that caused the suffering has changed. You can accept that the event occurred and that you suffered, but not allow it to cause you further suffering. That's easier said than done, but it is possible if someone wants to attempt it.