The family of a California grandmother says the government is standing in the way of her life-saving cancer treatment. Helen Huynh's doctors say she will die without a stem cell transplant, and while her sister in Vietnam is a perfect match, the U.S. Consulate there has refused to give her a temporary visa so far.

With her family by her bedside at the UC Irvine Medical Center's intensive care unit, Huynh is trying to beat leukemia, reports CBS News' Carter Evans. The 61-year-old was diagnosed with an aggressive form of the disease in February.

"We're taking it day by day. Every day with her is a gift right now," her daughter, Yvonne Murray, said.

Murray and her sister, Sharon Adams, say their mom's only hope is a stem cell transplant – ideally a rare, 100 percent match.

"And with 100 percent match, our possibility of it being it a successful transplant is very high," Adams said.

Doctors say Huynh's sister, Thuy Nguyen, is a perfect donor. She lives in Vietnam, which no one expected to be a problem. Doctors wrote letters urging the U.S. Consulate to grant Nguyen an emergency medical visa, saying "time is of the essence."

Yvonne Murray and Sharon Adams with their mother Helen Huynh. CBS News

Nguyen's visa application has now been denied four times. State Department spokesperson Heather Nauert told CBS News, "Stories like this always strike me at the heart." Since records are confidential, she was unable "to discuss specific visa cases."

"They're afraid that she would overextend her visa and stay in the U.S. illegally," Murray said.

The family emigrated to the U.S. in 1991 under a program for former officers in the South Vietnamese military. Huynh's husband, Vien, fought alongside American forces during the Vietnam War. They are all U.S. citizens.

"We never thought of ourselves as immigrants 'cause this is our home country. This is all the country that we know," Adams said.

"I feel a little bit heartbroken because my own government is the one that's preventing this whole thing from taking place," Murray said.

The family is getting some help from their congressman, Rep. Alan Lowenthal. In a statement provided to CBS News, he said: "This is outrageous and I am doing everything I can to make sure this wrong is corrected — and it will be corrected. I am working with Helen's family, the State Department, and the Department of Homeland Security, to make sure that we succeed in bringing Thuy to Helen as soon as possible."

Harvesting Nguyen's stem cells in Vietnam and shipping them to the U.S. is not a good option, says CBS News medical contributor and cancer specialist Dr. David Agus.

Yvonne Murray and Sharon Adams. CBS News

"I don't know of a case where they have done transplants where the patient and the donor are on different continents," Agus said.

"There has been people that has been suggesting to us, 'Hey why don't you go to Canada?' or 'Why doesn't she go to Vietnam and get this done?' But you think if your own country's not going to take care of you, why would another country, right?" Adams said. In the meantime, Murray and Adams are encouraging their mom to try to hold on a little longer while they try to cut through the red tape.

"I think it's a flaw in the visa system, the visa process, and it needs to change, and it's time that we make that change," Murray said.

The family has set up a GoFundMe page to help with expenses.