A baby born to a dying woman whose last wish was to hold her son is now thriving as a toddler, family members say.

Breanne Smaaslet, 22, was diagnosed with terminal osteosarcoma, a type of bone cancer, when she discovered she was pregnant.

She managed to stay alive long enough to give birth on Dec. 25, 2015. Baby Salvatore, shortened to Sal, was delivered via C-section at 26-and-a-half weeks.

Smaaslet died five days after holding her son for the first time, a month after her husband suddenly died.

"I know my baby will be in great hands when the time comes," she told CTV Vancouver before her death.

Now, relatives who are looking after the boy say he has shown remarkable growth and has left doctors stunned.

Sal was born weighing 1.9 pounds and spent the first four months of his life living in Surrey Memorial Hospital. Now, the toddler weighs 22 pounds and is considered to be a healthy weight and height for his age.

“We were told by multiple doctors he was never going to be here, he likely wouldn't survive his birth," said Smaaslet's aunt Rose Pachota who, along with her fiance, is raising Sal. "They're just amazed by his development."

She says looking after her great-nephew helps her remember the family members who have died.

"He brings us so much joy," she said. "We have this beautiful little boy who is a representation of the mom and dad."

Pachota's fiancé Frank Vargas agrees.

"I look forward to coming home so much," he said. "As soon as I see him, gives me the biggest smile and lights up my life."

With a report from CTV Vancouver's Michele Brunoro