Maranatha Road by Heather Bell Adams.
After Sadie’s son, Mark, is gone, she doesn’t have much use for other people, including her husband. The last person she wants to see is Tinley Greene, who shows up claiming she’s pregnant with Mark’s baby.
Sadie knows Tinley must be lying because Mark was engaged and never would have betrayed his fiancée. So she refuses to help, and she doesn’t breathe a word about it to anybody. But in a small, southern town like Garnet, nothing stays secret for long.
Once Sadie starts piecing together what happened to Mark, she discovers she was wrong about Tinley. And when her husband is rushed to the hospital, Sadie must hurry to undo her mistake before he runs out of time to meet their grandchild.