Undocumented Harvard student stranded in Mexico returns to U.S.

Dario Guerrero walks into the U.S. from Mexico at the San Ysidro border crossing in Tijuana, Mexico, Tuesday Oct. 21, 2014. Guerrero, a Mexico-born Harvard University student who was stuck for months in his native country after crossing the border without permission with his mother, who was seeking alternative cancer treatments, was finally granted a visa in Tijuana and can return home in Long Beach, California and then back to his studies in Harvard. (AP Photo/Alex Cossio)

Dario Guerrero pauses as he prepares to walk into the U.S. from Mexico at the San Ysidro border crossing in Tijuana, Mexico, Tuesday Oct. 21, 2014. Guerrero, a Mexico-born Harvard University student who was stuck for months in his native country after crossing the border without permission with his mother, who was seeking alternative cancer treatments, was finally granted a visa in Tijuana and can return home in Long Beach, California and then back to his studies in Harvard. (AP Photo/Alex Cossio)

In this Friday, Oct. 3, 2014 photo, Dario Guerrero, center, poses for a portrait with his grandparents Dario Guerrero Garrido and Crescencia Garcia Vazquez at their home in the outskirts of Mexico City. Guerrero, a Harvard University junior, accompanied his dying mother to Mexico without government permission, and is now unable to return to the United States. (AP Photo/Dario Lopez-Mills)

The Harvard student who was stuck in Mexico after leaving the U.S. to get help for his dying mother crossed the border into San Ysidro Tuesday.

Dario Guerrero Meneses, 21, is a Harvard film student who had been in Mexico since July when he took his mother there to get alternative cancer treatment.

When he tried to come back to the U.S. after his mother died in August, he was denied entry.

Guerrero came to the U.S. illegally with his family when he was 2 years old. In 2012, like thousands of other young undocumented immigrants under a deportation threat, Guerrero was granted a temporary reprieve under President Obama’s Deferred Action for Childhood Arrivals, or DACA.

Before he left the U.S., Guerrero applied for permission to enter Mexico and come back without consequence, but the respond didn’t come fast enough for him and his dying mother. When his mother became increasingly ill, he became desperate. He said he made the conscious decision to sacrifice his protected status, hoping to keep her alive.

“I understood the consequences,” Guerrero said.

Guerrero was recently granted humanitarian parole, but a technical issue at the U.S. consulate in Tijuana, Mexico denied him access to cross the border until Tuesday, his attorney said.

“Thankfully, everything was able to be worked out within a few months—it could’ve taken a lot longer,” Guerrero said. “I don’t regret it because I wouldn’t have wanted her to be alone in Mexico. I’m thankful that everything was able to work out in the end.”

He said he was documenting his journey for the past year and hopes to someday tell his story on the big screen.

The young man is headed to Long Beach, California to reunite with his family and will eventually return to Harvard.

Immigration activists claim he is an example of the nation’s broken immigration system.

“In a system that forces people to make risky decisions, the young man is one of our best. He should’ve never been through this,” said immigration activist and attorney, Andrea Guerrero.

For more stories from FOX 5 in San Diego click here.