Writing for documentaries

I'm wondering if anyone has experience writing documentary scripts or the like.

A presentation I worked on was shown at the opening of a museum in Poland, which has led to funding opening up for a larger project. It's a friend's story of growing up in Iron Curtain-era Poland, where his dad was a Solidarity organizer with access to banned books (generally, the classics) and the like, which my friend began reading from an early age. His dad became a political prisoner, they eventually moved to Canada, and my friend's background led to him bringing his literary bent to his life here.

We don't have any interest in fictionalizing it, nor would it make a good dramatic film as many core elements simply aren't visual. I'm not going to go into them here as it's my friend's life and specific enough to identify him.

I'm curious as to any tips or hints anyone might have in approaching a documentary-style film, especially using art or animation for visuals.

All roads lead to truth if you're willing to travel honestly.