When I needed to change a (non-flex) fare with NZ, they were very helpful. I the end I had to throw away the return. They refunded me half what I paid, plus the change of date fee i'd already paid when I submitted the death cert.

I think a lot of unwritten flexibilty in this circumstance depends on where the airline is based, and the compassion in the respective culture. New Zeland and the UK...compassion. Middle East, not so much. I also imagine somewhere like EY, there would be a massive amount of "escalation to managers", none of whom would want the buck to stop with them if they didn't follow the fare rules exactly. I'm sure their jobs would be on the line.