Postcards for a Songbird by Rebekah Crane

Everyone eventually leaves Wren Plumley. First it was her mother, then her best friend, and then her sister. Now living with only her cop father and her upended dreams, Wren feels stranded, like a songbird falling in a storm.
When Wilder, a sickly housebound teen, moves in next door, Wren finally finds what she’s always wanted—a person who can’t leave. But a chance meeting with Luca, the talkative, crush-worthy boy in her driver’s ed class, has Wren wondering if maybe she’s too quick to push people away. Soon, Wren finds herself caught between the safety of a friendship and a love worth fighting for.
Wren starts to dream again. But when postcards begin arriving from her sister, Wren must ultimately confront why her mother left fourteen years before and why her sister followed in her footsteps. For her new life to take flight, Wren will have to reconcile the heartbreaking beauty of lost dreams and the beautiful heartbreak of her new reality.