"All families have a secret. The secret is that they're not like other families." Alan Bennett.
Yesterday I found the interview I did with my elderly Auntie Lily in 1989 and spent hours capturing it digitally. It's done now so I can email it to any relatives who are interested. I'll be relieved not to have the sole responsibility of hanging on to it. I half-feared I might have lost it. It's the best day's work I ever did.
Lily was the doyenne of the family. The oldest of six and the longest-lived, she was also the company secretary of her father's business and a pillar of the local chapel so there wasn't anything she didn't know. (She also worked as a nanny in Germany in the 30s. We got round to that in a later chat.) She went through all the generations and talked about stuff that in my experience families only ever talk about when somebody has died and it's time to open the tin trunk full of documents. I suspect even my parents didn't fully know some of the things she told me about them.
Afterwards she would proudly tell other members of the family, "David's been to record me". She knew I was recording her because she was getting on ("I don't want to be in my nineties - when you're in your nineties you're just under t' feet") and she wasn't remotely squeamish about it. She was delighted that anyone was bothered about her experience. In our more pretentious times we would say it validated her contribution.
When I tell people I did this they say they'd love to do the same but they don't dare broach the subject in case it seems in bad taste. Everything important in life is. My advice is get on with it. Ring up the most reliable witness in your family and set a date.