(Reuters) - A California nurse whose husband is detained in Vietnam will attend President Donald Trump’s speech to the U.S. Congress on Tuesday, seeking to raise awareness in Washington and push harder on bipartisan attempts to free him.

Hanoi has accused Michael Phuong Minh Nguyen, a 55-year-old U.S. citizen, of engaging in activity against the Vietnamese government when he was visiting his country of birth last year. He has been jailed since his arrest in July.

His wife, Helen Nguyen, was invited to the U.S. capital for Trump’s State of the Union speech by U.S. Representative Katie Porter, a Democrat who represents the Southern California area where Nguyen lives.

“Here’s a woman who’s caring for her elderly parents, she’s caring for four kids and she’s caring for patients in our hospital system, and she’s terribly worried, understandably concerned, about the fate of her husband,” Porter said in a phone interview.

Porter said she regularly spoke to officials at the Trump administration’s State Department to discuss his case.

Porter represents part of Orange County, a Southern California area that is home to a large population of Vietnamese-Americans who fled as refugees from the U.S. war in Vietnam that ended in 1975.

The U.S. government has diplomatic relations with Communist-ruled Vietnam. But Porter said it had received little information from Hanoi on why Nguyen is detained. He is under investigation while he is jailed and has not been tried in court, she said.

Representatives of the government of Vietnam could not be reached for comment this week, when large parts of the country close for the Tet holiday.

Vietnamese authorities had not allowed the family to contact Nguyen, said his wife, who is caring for the couple’s four daughters.

“You’ve never been a single parent before, and all of a sudden it hits you all at once,” she said by phone.

Other Democrats are bringing guests intended to highlight the party’s differences with the president.

They include an illegal immigrant who used to work at Trump’s golf club in New Jersey, a Liberian immigrant facing potential deportation, and a climate scientist.

Trump has made fighting illegal immigration a signature part of his presidency, and has displayed skepticism over global warming that clashes with scientific consensus.