at the end of the trial , describe how grandpa and hiram each felt? why did they feel this way?

During the trial, Grampa becomes more agitated at Hiram for his desire to do what he feels is right.

Hiram slowly starts to piece together that perhaps the grandfather knows more than he's letting on. It turns out, Grampa helped to lynch Emmett Till himself.

Hiram is never actually allowed to testify and the two murderers are acquitted. Still, he confronts his grandfather for his racial prejudice, his racism, and his willingness to commit murder. The grandfather is stone cold. He admits his involvement, but is not remorseful whatsoever. Hiram leaves back to Arizona and reconnects with his own father, understanding that his dad was probably the victim of abuse, since Grampa is violent and hateful.