How does John Thornton react to the inexperienced prospectors’ abuse of Buck, as well as their eventual fate? What does this tell you about him

Thornton refuses to let Hal and company abuse Buck any further. He threatens to beat them if they whip Buck one more time. I don't think Thornton was very sad when they drowned under the ice from their own foolishness. Thornton had a deep respect for sled dogs.