An Angel For Duane & Gladys by Joanne Wiklund

Duane & Gladys, grieving over the loss of their adult son, try to find an adventure to take their mind off their pain. They buy the contents of a storage shed and get a Palamino in the bargain. They also get more grief of a different kind when the rightful owner turns up to help them console the horse over the loss of his owner. The adventure they were looking for heats up when a natural disaster hits their area, and a local cop finds discrepancies over the way their son died.