DALLAS (CBSDFW.COM) – Demonstrators stood during a funeral Monday for a student pilot from China who died in Denton in April.

Silently holding signs reading “Justice for Yang” and “End Discrimination Now,” they sought to draw attention to questions surrounding the suicide of Yang Yan.

Yang Yan (courtesy: Yan family)

Yan’s family, who traveled to Texas for the service, is also expected to stay in the country for an undetermined length of time to get more answers about what happened to the 21-year-old.

The chapel at Restland Funeral Home in Dallas was mostly filled with students who trained with Yan at the U.S. Aviation Academy in Denton.

Some of those students have spoken out anonymously since Yan’s death, claiming he had struggled to get enough training time to advance as a pilot. They have also complained instructors generally disregard Chinese students, and questioned rules including travel and language restrictions.

Ongoing Questions Into Death Of Trainee At North Texas Flight School

In a letter last month, the school’s CEO wrote that Yan did not have the ability to become a pilot, and it had asked the airline paying for his training to have him return to China. It said training rules were often at the request of airline clients.

Mark Taylor, the company’s executive vice president, denied any mistreatment in an interview last month.

He spoke at the service Monday, calling for understanding at a difficult time.

In an interview following the service, Yan’s mother said her whole family was proud of her son, who was taking care of them. Speaking through a translator though, she said he never let on if he was facing difficulties during training.

“When he have a frustration or hardship here, he often did not talk to the family. He does not want anybody to be worried for him,” an interpreter said.

Supporters of the family said they are looking for legal representation now to pursue the issue.

An online fundraising effort has pulled in nearly $20,000 in the last four days.