When Margery Hop Wong bade her older brother goodbye in 1943, she was just a 12-year-old girl who loved it when he took her for joy rides in his used convertible around the apple orchards their family worked.

Yuen Hop left their home in Sebastopol, Calif., a small town 55 miles north of San Francisco, at 19 to join the U.S. Army. His little sister never saw him again. She knew he had died in the war, but she did not know how. Or where. Or what had happened to his body.

On Friday, Ms. Wong, now 94, sat in the front pew of a mortuary just south of her home in San Francisco, her brother’s remains in a casket draped in an American flag. Younger generations of the Hop family and military veterans filled the rows behind her as a singer led the group in “Amazing Grace.”

For 80 years, Sergeant Hop was lost. Now, he was found.

Ms. Wong was the youngest of seven children born to Gin and Chan Hop, immigrants from China who spoke Cantonese and struggled to communicate with their American-born children, who grew up speaking English.

Life was difficult because of anti-Chinese sentiment fueled by the Chinese Exclusion Act, passed by Congress in 1882 to dramatically restrict Chinese immigration. Chinese immigrants were regularly prohibited from living or working where they wanted, Ms. Wong recalled in an interview. She said her brother was proud to have scraped together money working as a mechanic and drying apples to buy a used convertible and tried to make life fun for his brothers and sisters.