I'm so sorry. Your situation is tough because of the uncertainties and circumstances. Depending on whether or not you know anyone else who knew this person, you might be in the difficult position of not being able to express your grief or share it with others who can truly appreciate the depth of your grief and make you feel as if your pain is being heard.
The second book I'm going to mention addresses the issues of "Where does the love go?" and questions the linear timeline ideas we have about our lives, our losses. Both books question the idea grief is something we need to "get over." I got rid of that idea years ago after realizing I am very happy I can feel such pain because it means that we loved truly and deeply.
Maybe you can check out these books online and see if they might be something you would find helpful:
"Bearing the Unbearable: Love, Loss and the Heartbreaking Path of Grief" by Joanne Cacciatore. (I'll post the link to her websites below. There is some help on those websites.)
"No Death, No Fear: Comforting Wisdom for Life" by Thich Nhat Hanh. This isn't really a book about grief but out life, loss, death and fear, but when I finished reading it I had a different perspective about grief and loss. I have to tell you that this book is by a Buddhist, so although it is not heavy handed in any way about religion, it is written from an Eastern perspective that discusses life from a non-dual perspective (where linear time is not so important). This book was so good that I just ordered a second book by him that is specifically on the topic of loss, grief and bereavement (but haven't received yet).
From my heart I wish you the best.
Links to Dr. Cacciatore's websites:
https://www.centerforlossandtrauma.com/
https://www.missfoundation.org/ (its mission statement is to help parents who have lost a child, but again there is some helpful information for generalized grief)
Sending you love and support