An Unlikely Friendship — R. William Rogers

Wesley Swanson had just a few months prior turned thirteen and was now well on his way to becoming an integral part of the Circle C cattle ranching outfit. But all that gets shoved aside after an encounter with a massive grizzly that changes everything for him and the rest of the Clarksons and Swansons
After being injured as a result of a mishap while at the mercy of his fleeing mare, Wes is eventually taken prisoner by the ruthless Comanches and held captive with the intent of training him as a helper for Angry Wolf, his wife, Gentle As The Breeze, and daughter, Little Fawn.
With help from their friends the Utes, Wes's family learns of his capture and settles on a plan to bargain with the Comanches for his release. However, things get complicated after Wes attempts an ill-fated escape and suffers even further injury during his recapture.
With his family continuing to put their plan into effect, Wes is cared for by the young maiden, Little Fawn, who has been taught to speak the language of the White Eye by Billy Soaring Bird, who many summers before, was also brought to the village as a captive.
After the plan to bargain for Wes's release is unavoidably put on hold because of an unexpected snag, it's the stealing of Little Fawn's friend, Morning Dove, that becomes a determining factor in the final outcome.