Greg and Elaine Smith of Pitt Meadows, B.C., found a surrogate mother in Mexico through a paid clinic, because they couldn't find one in Canada, said Greg Smith's aunt Linda Pruden.
Babies Ayden and Ariana were born prematurely on Jan. 8 at 31 weeks, weighing just three pounds each, and have since lost weight and suffered numerous complications, said Pruden, who was in Mexico when the babies were born.
"They had it all planned out the way they thought it would go perfect, but of course it didn't, and now it's just turned into a nightmare."
A crowdfunding site set up by the extended family estimates the Smiths have spent $100,000 so far on the babies' care.
Both preemies remain in the neonatal care intensive care unit at Hospital Angeles in Villahermosa, Mexico.
Their Canadian parents are scared for the babies' health and unsure how to navigate the Mexican medical system. Pruden told CBC News the hospital was requiring payment of $5,000 Cdn per day, payable every four days.
"[Greg] is just a basketcase. He's a walking emotional wreck, and Elaine is the same way."
'I think they need better care'
Both babies are on respirators after their lungs stopped working, which is a common complication with premature babies. Ariana has also suffered several infections, and a serious brain bleed, said Pruden.
The Smiths want to bring the babies to B.C. Children's Hospital in Vancouver for medical care, but are being told they need to wait, said Pruden.
"We don't know if we should wait, if we can wait. I think they need better care than they're being given," she said.
According to the family, the largest stumbling block in bringing the babies home is Mexican authorities haven't issued birth certificates, which are required to start the immigration process.
The hospital is telling the Smiths a notary is required before the certificates can be issued, and it's not safe for the notary to enter the NICU, said Pruden.
The family is questioning that explanation.
"Mexican lawyers have contacted us and said it's all who you see and who you bribe, and then things will be done. So that's our next step," said Pruden.
A nurse in the hospital told CBC News that Ayden would be healthy enough to travel in a few days, but Ariana was in critical condition and could not travel. She did not have information on the birth certificate.