Well,he dead just dead,unless you restart a previous save files before Olaf was dead
After free Olaf from Cotton Fields, the only special interaction with him is when you return to Your Bunker. After that, he acts just like any other muted caravan member, with his death having no impact in the storyline.
I never tested let him die before going back to the Bunker. If you are lucky, maybe it will still trigger the kidnapping of the bunker people, only skipping Olaf's reaction, so the storyline can still progress. If not, reload a previous save.