OAKLAND -- Two years in a row, George Moa begged his parents to let him and his teenage cousins drive to Las Vegas to watch the West's biggest pro rugby tournament. And both times, Lani and Taufa Moa refused.

But this year they let the 19-year-old go. They still think it was the right decision even though the trip ended in tragedy.

After a weekend of rugby, buffets and concerts, George Moa fell asleep behind the wheel of a rented SUV about 50 miles southwest of Bakersfield on Monday afternoon as the clan headed home to Oakland, family members said.

Moa, who police said was driving nearly 90 mph, drifted into the center divider and flipped the vehicle. He was killed almost instantly. So were his cousins, David Moa, 19, Malia Moa, 17, and Rachel Fisi'iahi, 19. David and Malia Moa are siblings and Fisi'iahi is their half-sister. A fourth passenger, their cousin, Hunter Halatoa, 17, suffered injuries not considered life-threatening.

"There is nothing you can do as the parents," George's father, Lani Moa, said Wednesday. "This is what they wanted. They are 19 years old. It's so sad they died."

The teens were part of a big Tongan family that loves rugby, music and each other. They each had multiple siblings and dozens of cousins. Family get-togethers at an East Oakland home draw more than 30 people every Saturday.

Three of the teens were members of a family band called Valu Fa. All of them played rugby. After countless parentally supervised road trips for concerts and rugby matches, the three Moa children wanted to take in Las Vegas and the International Rugby Sevens Tournament free from adult supervision, family members said.

"They always begged us, 'When are you going to let us go on our own?'" Lani Moa said. "This time, I said to my wife, 'I think they're right.' They wanted to prove they could do it on their own. We allowed them to do what they wanted."

Lani Moa said his son emailed him photos of the fun they were having in Las Vegas. On Sunday, after the rugby tournament was over, they went to a reggae concert and stayed out most of the night. "I woke up at 5 a.m. to them walking in the room," said Jennifer Tuinauvai, a friend of Fisi'iahi's who shared a hotel room with the family.

After napping for several hours, they left for Oakland about 1 p.m., Tuinauvai said. Fisi'iahi had originally planned to fly to Las Vegas, but agreed to go with her relatives so there would be more than one driver making the trip.

According to accounts from those in contact with the lone survivor, Fisi'iahi started off driving but was so tired, she let George Moa take the wheel.

Halatoa was sleeping during the trip, but woke up as the car started swerving. "When he called out, George was asleep," Tuinauvai said.

She was told that several people in the car weren't wearing seat belts. California City police Chief Eric Hurtado said two of the dead and the lone survivor were ejected from the vehicle. Tests to determine if drugs or alcohol were a factor are pending, Hurtado said.

Family members described the victims as fun-loving and caring kids. Malia Moa was a Rachel Fisi'iahi at Aspire Academy in Oakland, where she starred on the basketball team.

George Moa was working at a packaging plant and preparing to go back to school, his parents said.

Fisi'iahi graduated from Oakland High School in 2011 and was studying forensics at City College of San Francisco, while also holding down a job to help her disabled parents. "Rachel is a loving person," her mother, Finau Fisi'iahi, said. "She loves everybody. She never says no to anybody."

David Moa was a Rachel Fisi'iahi at Laney College after graduating from Castlemont High School, where he played football. "He had a real gentle soul," said John Beam, the football coach at Laney College. "He had a good smile on his face. And he was finding himself."

Halatoa still attends Castlemont, where Rachel Fisi'iahis covered a wall with handwritten notes to him and his cousins. A memorial with tea candles rested under a photo of David Moa. The school will hold a memorial for him Thursday.

At the family home on Wednesday, Lani and Taufa Moa were comforted by more than 20 relatives. Lani especially kept a stiff upper lip.

"The pain inside us, you don't see it," he said. "Every time I'm by myself, there's tears in my eyes."