The absence of sparrows / by Kurt Kirchmeier.

Enhanced descriptions from Syndetics:

Stranger Things meets The Stand in this haunting coming-of-age novel about a plague that brings the world to a halt -- and the boy who believes that his town's missing sparrows can save his family.
In the small town of Griever's Mill, eleven-year-old Ben Cameron is expecting to finish off his summer of relaxing and bird-watching without a hitch. But everything goes wrong when dark clouds roll in.
Old Man Crandall is the first to change -- human one minute and a glass statue the next. Soon it's happening across the world. Dark clouds fill the sky and, at random, people are turned into frozen versions of themselves. There's nowhere to run, nowhere to hide, and no one knows how to stop it.
With his mom on the verge of a breakdown, and his brother intent on following the dubious plans put forth by a nameless voice on the radio, Ben must hold out hope that his town's missing sparrows will return with everyone's souls before the glass plague takes them away forever.