VANCOUVER -- A Metro Vancouver family has launched an online fundraiser to give back to the stranger who saved their son's life.

Liam Miller's parents organized a GoFundMe campaign they say has the goal of raising $3,500 to give the man who donated his bone marrow.

The donor had to take a significant amount of unpaid time off work for the invasive procedure to help save Liam, who was one at the time.

As a baby, Liam was diagnosed with a life-threatening disorder known as Wiskott-Aldrich Syndrome, which the family says has characteristics of both leukemia and hemophilia. Without a transplant, doctors told the Miller family Liam was unlikely to live past his fifth birthday.

"We're just trying to rally up as much of a compensation for his losses, his time off and just a thank you because it was honestly a completely selfless gift," Brandon Miller, Liam's dad, told CTV News Vancouver.

"He did it with the expectation of nothing in return. He deserves much more than I can possibly give him."

According to Canadian Blood Services, donating bone marrow is a surgical process that involves anesthesia and takes up to 90 minutes. Full recovery time can take several weeks.

As of Monday morning, the campaign had raised more than $6,500.