Brayden said he was thrown from the bike spinning and things became "like slow motion".
"I went to put my hand down with my eyes shut - I think that's when I broke my arm," he said. "I could see a head - some lady - I yelled for help and she covered my leg up and called an ambulance. She called three times because her phone died - so she had to grab someone else's."
Meanwhile Mr Bullivan said he was running around trying to find his son. "I thought the worst. It was a big relief when I saw him move. I saw his broken arm straight away - it was all swollen up."
Brayden broke both bones in one arm, shattered the elbow in the other arm and grazed his knee to the bone.
His mother Terri Bullivan said he was miserable when doctors told him he could not go home for Christmas, after which several days were planned at Whirinaki where he could ride his motorcycle on the beach with visiting relatives from Auckland.
Brayden said it looked to be his worst Christmas.
But Brayden's progress has enabled doctors to reassess Christmas Day.
Occupational therapists established his family were able to transfer Brayden to a wheelchair, enabling him to spend Christmas morning at home.
On the hospital's Christmas menu was roast lamb with mint jelly or gravy, roast chicken and gravy served with mashed potato, roasted vegetables and minted peas. Dessert was Christmas pudding, custard or pavlova, with berry coulis and cream.
While Brayden will have an idle holiday period, his father won't.
"I have to replace the whole front end - forks, bars and wheel - he's bent the whole lot. He was lucky he was wearing a full face helmet."