Know that there are many paths. Someone may be at the end of their journey but still be present and alive. Some may come and go in their process. Some may just go, very simply. Some may change their path so that they are still alive. Some may come back from a great illness. There are choices in every turn for you to make.
Some may claim that they are finished and ready to go but then stay. They may be fighting the whole time. They struggle with life and they struggle with death. Start observing people and how their lives work for them or don’t work for them. You are not judging this. You are just observing what seems to work and what doesn’t seem to work. You may then apply this to your own life. Now look at your own life objectively and see what you notice in your own behaviors.