Fictional Mystery - MC is boy afraid of the ocean tries to solve a mystery in coastal town. Read around 2017-2020. Spoiler.

[Jennifer R. McGough]

Title for book read around 2017-2020. A young boy (likely on the spectrum) lives with his dad in a coastal town. Dad is an avid swimmer in the ocean. Boy is afraid of the water. Boy tries to solve a mystery in town and comes to believe his dad may not be his dad. Dad saved him from his mentally ill mother trying to drown him years ago.