Being Mortal by Atul Gawande is filed as a medical book. It is really a book about how modern medicine has taken the end of life and turned it into a series of technical problems, and what you can do — as a patient, as an adult child, as a caregiver — to fight back against that. It is one of the few books I have read twice.
The key idea, which changes how you talk to a doctor: instead of asking “what treatments are available?” you ask “what are you hoping to achieve, and what are you afraid of?” That reframing sounds obvious once you read it. It is not obvious in practice. Most families discover it too late.
I gave a copy to my parents when they were in their late sixties, along with a note that said “you do not have to read this now.” Both did. Both said the conversation about what quality of life meant, specifically, was the most useful conversation we had had as a family in years. That is what this book unlocks. It is not for you when you are dying. It is for you now, before anyone in your family gets sick.