This was a hard topic to tackle and read about. Basically, we're all gonna die.
The first half of the book is more about aging and assisted care and nursing homes. Even if you can no longer live on your own, the decisions you have over your life can make a big difference (can you decorate your room, get up when you want to, lock your door, have a drink, eat a donut?).
The second half is more about hospice and palliative treatment for people who are terminally ill. My big takeaway is that it's s0 important to have those conversations early on to figure out what you want - otherwise someone else will be making those decisions for you. It's important to understand your fears and goals to be able the decide whether you want to live the best you can with what you have left or whether you want to sacrifice the life you have left for a chance of more time later. There's tools here to ask those questions to get to a place where you really understand the meaning behind different medical options. When is life still worth living? There was also some interesting stuff near the end about your "experiencing self" and your "remembering self" - you only really remember the peak of an experience and the end of the experience.
It's also a very personal book - he tells stories both of what he's seen as a doctor, but also the last years of his own father's life, and how his family navigated those difficult choices. This was a hard book to read but it has a lot to think about!