Student Stuck in Mexico After Seeing Dying Mom Granted Visa to Return to US

— -- A junior at Harvard University who is an undocumented immigrant has been granted a visa to return to the United States after he was stranded in Mexico while trying to save his mother with an experimental cancer treatment.

Dario Guerrero knew that he needed permission from U.S. Customs and Immigration to leave the country but because of his mother's deteriorating kidney cancer, he felt he couldn't wait for an official response any longer, his lawyer said.

"The U.S. Citizenship and Immigration Service did a great thing just a few minutes ago and they granted and approved Dario's humanitarian parole visa request so he can return to America. He should be back in America in a few days," Guerrero's lawyer, Alan Klein, told ABC News today.

Guerrero, 21, said he drove down through Tijuana because he wanted to see his dying mother.

"I thought immigration was being so obtuse about my case. And I decided to take my risk and deal with the consequences later," Guerrero told ABC News earlier today, before he learned that he had been granted a humanitarian parole visa.

Guerrero's mother died in August.

"He acted impulsively," Klein said.

"I didn't think it would take this long," Guerrero told ABC News. "I thought I'd be back in time for fall semester. I've learned a lot –- but I'm glad I made this decision."

Guerrero's parents brought him to California when he was 2 years old, becoming undocumented residents when they overstayed their tourist visas, his lawyer said.

He didn't learn of his immigration status until he was 16, when the community college where he was taking courses flagged up that there was a problem with the social security number that he submitted. Guerrero detailed how he navigated the stressful application process and eventually got a full scholarship to Harvard in an article for The Washington Post.

When his mother's health deteriorated dramatically this summer, his attention turned from his film studies major at Harvard to his family in California.

His mother returned to Mexico in July "to receive treatment that she wasn't able to get or afford in America because she was undocumented," Klein said, and though Guerrero stayed at home in California with his father and two younger siblings, her condition began to deteriorate.

Guerrero applied for a parole exception, but did not want to wait any longer for a response.

"His father told him, 'Go be with your mother on her dying day,'" Klein told ABC News.

Guerrero told the Associated Press that he regrets the decision to leave, largely because his mother's treatment didn't save her and he believes she would have liked to have been with her whole family. Dario's father stayed in California with his younger sister while he and his brother went to be at their mother's side.

"Then we still had hope -- and if we delayed that treatment any longer because of immigration issues, I don't think I would have been able to forgive myself," he told the AP.

"My mom had a lot of ups and downs," Guerrero told the AP. "The decision to actually leave was made overnight."

Colin Manning, a spokesman for Harvard College, confirmed that Guerrero is a student at the school, "but federal student privacy laws prohibit me from commenting further."

"While I cannot comment on any specific student, generally speaking, Harvard works to ensure it is doing what it can to support its students both on and off campus since it is our goal that all students complete their undergraduate education," Manning said in a statement to ABC News.