Oh, this is dreamlike and lovely, and manages to craft an atmosphere that I really enjoy but can't really describe. It's a story and feeling that feels both new and old at the same time, and I love it so much! As GamingDama said in another comment, this story naturally lends itself to the readers thinking about the characters in the future, and just in general as well.
As for the themes of death...man. Okay, so fun fact about me, two years ago I took a course on spirituality/faith and death, taught by a person who had briefly been interested in becoming a mortician and working with the dead/ dead bodies (I don't remember the exact details). It was an amazing experience. I don't mean that in the sense that it was pleasant, but the fact that the feeling of discussing death, grief, trauma and the afterlife with a group of people I had grown to trust, under the guidance of a teacher, is something I feel like more people need to experience. I'm saying all this to say that I genuinely kind of want to talk about this book with the person who taught that class. I thought of her often while reading it.
All in all, great job!