The silent gift / Michael Landon, Jr. and Cindy Kelley.

Enhanced descriptions from Syndetics:

The 1930s were a decade of enormous uncertainty for the world, for America, and in particular for one lonely, struggling mother and her disabled son. Their story is one of love and enormous sacrifices in the face of circumstances horrendous beyond belief. When her husband leaves her for someone whose time isn't wrapped up in a silent, handicapped kid, Mary and little Jack are out on their own in a world that has no room for the poor and disabled. Especially not at a time when most Americans are simply trying to survive their economic woes and job losses.But then arrives The Gift ... where has it come from, and why? How can a young boy who can neither hear nor speak provide comfort, direction, and sometimes challenges to seekers who learn of the special ability? Whatever the source, its presence brings a single shaft of light and hope to Mary and her beloved Jack. Will it be enough?