Story highlights Three friends set out on a fishing trip on February 24 from San Carlos, Panama

The boat's engine died; it was found adrift in the Pacific some 600 miles away

Adrian Vasquez survived on raw fish and rainwater, his mother says

His friends died, and he had to dispose of their decomposing bodies, she says

It was a Friday evening in February when Adrian Vasquez, an 18-year-old from the town of Rio Hato, Panama, accepted an invitation from two friends to accompany them on what was proposed as an overnight fishing expedition.

Their plan, according to Vasquez's mother, Nilsa de la Cruz, "was to return the following morning. On February 24, they left from Ensenada Beach in the town of San Carlos aboard a small fishing boat."

But the following morning came and went without their return, and the Vasquez family started looking for the 18-year-old and his friends.

Arnaldo Vasquez, the teen's father and a hotel worker, asked fishermen to search for them along the shore from which they had departed, and his mother prayed at home with relatives and friends. Soon after, the Panamanian navy joined the search, sending ships and airplanes to look for Vasquez, Oropeces Betancourt, 24, and Fernando Osorio,16.

For nearly a month, their fate remained a mystery. But on March 21, fishermen spotted the boat, the Fifty Cents, adrift north of the Galapagos Islands, nearly 600 miles from where it had launched.

After being alerted by the fishermen, the Ecuadorian navy rescued the lone crew member.

In a statement, Rear Adm. Freddy Garcia Calle said Vasquez showed "severe signs of dehydration and lack of nutrition."

He said the survivor had thrown his friends' bodies into the ocean "because they had become badly decomposed."

Vasquez returned Tuesday to Panama City on a commercial flight. According to his mother, he had lost 20 pounds. "After 28 days of anguish, after praying to God that he be found alive ... this is indeed a miracle," de la Cruz said.

She said her son told her the fishing trip had started out well. The three caught plenty of fish. But the boat's engine died without warning and, with no tools and scant navigational experience, there was little the trio could do, de la Cruz told CNN.

Soon, currents had swept their boat out into the Pacific, far from the coast. De la Cruz said they ate raw fish and drank rainwater. She did not detail how the other two died. The Ecuadorian navy has said it is not investigating the deaths and considers the incident a rescue operation.

De la Cruz described an emotional reunion Tuesday at the airport in Panama City, where relatives hugged Vasquez and cried tears of joy. He was taken to his home in Rio Hato, in Panama's Coclé province, southwest of the capital.

Reached Wednesday by phone, de la Cruz said her son "has been sleeping a lot. We don't want to ask him any questions because we know he's traumatized. He's surrounded by the family. We're loving on him and trying to help him feel better. We're going to take him to a psychologist tomorrow."

De la Cruz said her son is "a very loving and hardworking young man" who enjoys spending time with his brothers and loves soccer.

She said the family is taking one day at a time and trying to support her son.

"For us, this is an opportunity to get closer as a family, to be more understanding and loving," she said.