Caleb and Anna see Jacob’s arm around Sarah. Describe their reactions

From the text:

Papa said nothing. But he put his arm around her, and leaned over to rest his chin in her hair. I closed my eyes, suddenly remembering Mama and Papa standing that way, Mama smaller than Sarah, her hair fair against Papa's shoulder. When I opened my eyes again, it was Sarah standing there. Caleb looked at me and smiled and smiled until he could smile no more.