Sorry to hear of your loss.

I'd a similar situation with Singapore Airlines a few years ago. It was a restricted ticket and my Mum was diagnosed with a terminal illness with a short time left.

Unfortunately in our case SQ only refunded half the ticket and I had to claim on our travel insurance for the remainder. If you have travel insurance it may be worth just taking that route as I remember getting very distressed at having to repeat the details to several people and travel insurance at least resolved it.