The boy, who has been identified as Felipe Gomez Alonzo, was taken to a New Mexico hospital twice on the day of his death by CBP officials alongside his father, after they had immigrated to the U.S. days earlier.
His mother, Catarina Alonzo Perez, is still in Guatemala and spoke to local newspaper Prensa Libre, saying she wants her son's remains to be sent back to their home but wants her husband to be allowed to stay in the U.S.
"I want them to bring my son here soon," Alonzo Perez, told Prensa Libre. "I need to see him soon and I’m very sad because he died."
The boy's 21-year-old stepsister, Catarina Gomez Lucas, spoke to The Associated Press and said that the family had heard that it might be easier to gain access to the United States if a child was with an adult.
"We heard rumors that they could pass [into the United States]. They said they could pass with the children," said Gomez Lucas, who shares the same father as Felipe.
The boy's mother told the AP, through Gomez Lucas, that her son was healthy when he left on the journey, and she had spoken to him the day before he and his father were taken into custody by CBP officials, which happened on Dec. 18.
"He wasn’t sick on the way; he wasn’t sick here," Alonzo Perez told the AP via Gomez Lucas.
Gomez Lucas said that the family had heard from their father, Agustin Gomez, throughout the journey but that stopped on Dec. 18. They next spoke to him again on Christmas, hours after Felipe died.
"He told us that [Felipe] was fine all day, that he was playing with other children. But then he said he felt bad and his stomach ached," Gomez Lucas recalled her father saying.
She told the AP that their father was dealing with a massive debt. He had recently sold land and earned about $6 a day, but that was not enough to support his family, so he decided to take out a loan and travel to the U.S., she said.
Felipe "always wanted a bicycle" and their father saw the U.S. as a way to help get their family out of poverty, Gomez Lucas said.
"My father is suffering because of the boy. We do not know what will happen. We have nothing to live with. We do not have money," she added.