The Haunting of the Sleeping Harpy by Marie Wilkens

After losing their five-month-old child to SIDS, Damien and Sophia struggle to keep their marriage from falling apart. But when Damien's estranged grandfather suddenly passes, naming Damien heir to the private estate, Damien sees it as an opportunity for the couple to escape the empty crib at home. Upon their arrival to Loray Island, Damien uncovers horrifying family secrets his late grandfather had wanted to remain buried. Suddenly, the island Damien believed was the answer to his prayers quickly transforms into the subject of his nightmares.