Sydney boy Nicholas Tadros is facing a serious test on his body as he undergoes a major operation seven days after a helicopter crash that killed his mother and three others.

The 10-year-old is being treated in Queensland Children's Hospital after the chopper he was in collided with another helicopter and crashed into a sand bar near Sea World at the Gold Coast on December 2.

Four people in the helicopter died, including his mother Vanessa, 36, Britons Ron and Diane Hughes, 65 and 57, and 40-year-old pilot Ashley Jenkinson.

Nicholas was scheduled to undergo six surgeries for broken bones in his legs and hands in a six-hour operation on Tuesday, according to his father Simon Sim.

"This will be a major test on his body, lungs and heart," he wrote in a text message to friend Charlie Bakhos that was posted on Facebook.

"I know it's a bit late now to ask (people) to pray for tomorrow, I always miss the prayer sessions with you, it's too full on for me (at the moment)."

Mr Bakhos also urged people to pray for Nicholas, saying he had already had "some miracles" with his improving condition and surviving the "high-risk" transfer to Brisbane.

Victorian boy Leon de Silva, aged nine, who was in the same helicopter, is in a stable condition at the hospital after suffering a brain injury in the accident.

Leon's mother Winnie, 33, is also stable in a Gold Coast hospital after undergoing another operation for her injuries, which include two broken legs, a damaged left knee, a broken right shoulder and a broken collarbone.

"She's had a lot of pain, but her thoughts are really with Leon, so she's a tough girl," husband Neil de Silva told Seven's Sunrise program on Tuesday.

He spent Monday at the side of Leon, who was asleep for most of the day, but at one point said the word "dad" and gave him a thumbs-up.

New Zealand passengers Elmarie Steenberg and Marle Swart who suffered glass shrapnel injuries in the second helicopter are looking forward to continuing their recovery at home.

In a statement on the weekend, the Steenberg and Swart families expressed their sympathies to the other victims and their families, saying they continued to pray for Nicholas, Leon and Winnie.

"As we return home to New Zealand, we feel eternally grateful to have been spared and thank God for every day we can spend with our loved ones," the women and their husbands said.

The ATSB is probing the crash and expects to complete the investigation between July and September 2024.

Video footage from one of the choppers shows a passenger trying to warn pilot Michael James about the oncoming helicopter before the collision.

British-born pilot Mr Jenkinson will be farewelled by family and friends at a funeral service at Southport on Friday afternoon.

© AAP 2023