Death and the documentary

When you make a long duration documentary (like I've been doing for over a year now), you know that a certain amount of changes will take place in the lives of the people you interview. But when that becomes death, it really shakes you and shocks you.
One of the key interviews in my documentary was a brother of the senior protagonist, uncle and granduncle to the other protagonists. He was not just an interviewee, he was my guide to the family's past in another town- the old houses they had lived in, the old shops the family members had run- only he knew it all. He was seventy years old, but had applied hair dye for his hair for the interview, put on his best clothes and lovingly spent a day helping me with the documentary. In fact the last shots we took of him and with him were in the corner of the family's graves at the local cemetry.
When we started putting together the documentary, he naturally featured in a prominent role, providing information and even humour with his old world comments.
Now suddenly he is no more, before the documentary is out in public.
Aside of purely personal emotions (he had become close to my wife and myself in that shooting spell), I was left wondering about how to handle the whole issue of death in the documentary.
In this particular project, at least I had his interview- for another person I met him, spent time with him discussed the interview and the next day he was no more. That was pretty devastating.
Another person I met after he declined to be interviewed (saying he was nervous), but we chatted along and I realised how much he would have enriched the documentary.  A few days later he was gone.
Yes, I've read those quotes of Andre Gide: Cinema records death at work. But to actually experience it is a deeply moving and humbling experience.
You realise that its a privilege to do a documentary, to do interviews where people talk- they're never going to be the same again.
The very switching on of the camera is a transcendental act- you're transcending the moment as it exists in time.
If that's not a very very big privilege, I don't know what is.