I have only found two really useful books about dying. In the seventies Elizabeth Kubler-Ross wrote "On Death and Dying". As a medical teaching researcher she investigated the lack of training for doctors regarding their patients personal experience of dying, and how to relate to it. She identified the five typical stages of this process as being Denial, Anger, Bargaining, Depression and Acceptance, and had a huge impact on millions with this insight.
More recently, Ganga Stone's hands-on approach "Start the Conversation: The Book About Death You Were Hoping to Find" comes from the personal experience of being a dedicated consultant to the terminally ill, their families and caregivers. She has powerful insights into the psychology and emotional pathways available to each of these positions, and focuses on the practical and achievable steps in reaching Acceptance. Her book is here.
There is no better point of reference for a musician wanting to go deeper into their art than to incorporate it with their personal demise. It puts all else into perspective, and engages the heart towards courage and truth.