Chelsea M. Cameron
From Goodreads: "Seventeen-year-old Ava-Claire Sullivan isn't one for doing the expected. Especially when she finds out her mother's cancer is terminal. After a crying session in the local cemetery where she's attacked by one strange guy and saved by another, she doesn't call the cops. Because those guys definitely weren't your average hooligans.
And the one who sort-of saved her? Well, he's odd. He doesn't seem to breathe or smile or have anything better to do than wait in the cemetery for Ava to come back. Which she does. Call it morbid curiosity. Even after her warns her that he's dangerous, she can't stop wanting to see him, talk to him, be with him.
There's something about Peter that provides a much-needed escape from her mother's diagnosis and her tenuous relationship with her father. Even her best friends Jamie and Texas don't know what it's like to face death. But Peter does. He already has. He also made a promise a long time ago that could destroy both of them.
When everything in your life is falling apart, what are you willing to give up to hold onto the one thing that could last forever?"