The ending of Where Things Come Back seems quite abrupt when you think about how the entire novel has led up to the moment that Gabriel comes back. But instead of getting, say, a chapter's worth of attention, this moment comes in the very last paragraph, which seems odd:
When one is sitting in his bedroom and, happening to glance out the window, sees his little brother walking slowly down the driveway, he immediately jumps up, knocks over a stack of magazines piled up beside him, and runs through the doorway and down the hall. (21.16)
Instead of letting the reader see the aftermath—how Mr. and Mrs. Witter react, how the return of his brother frees Cullen from worry, the first thing the brothers say to each other, and the like—the book ends right at the scene where Gabriel and Cullen are gazing at each other for the first time in months. The relief is palpable. And perhaps the whole point is that it doesn't matter what comes next. What really matters is that Gabriel is finally home. Things are back to the normal that Cullen has so often lamented throughout the book, but suddenly, now normal is just right.