He had already bought a V8 ute for him and his brother to work on since getting home in August, Mum Kim Ostern said.
Instead of using the hoist to lift the engine, the pair used it to hoist Cooper over the motor so he could instruct Geordie about what he wanted done, Ostern said.
While Cooper can't move his fingers, he could lift his right arm up to his face and the family were hopeful he might regain some more movement in it to help him become more independent.
"He's doing so much more than they ever said he would do," she said.
In hospital he learnt to use a computer mouse which he could operate with his head to allow him to use Facebook and watch Netflix.
His first Facebook post since the accident came in late May when he used the mouse to type two simple words: "I'm back".
Back in Whanganui, where he moved to from Tauranga just days before the accident, 20-year-old Geordie is Cooper's carer and tries to make life as normal as possible for him.
"Like a typical 16-year-old he doesn't like to hang out with his mum," Ostern laughed.
While there were hard times, Cooper was getting on with life and was already looking to the future.
He has told his mum he wants to do a mouth painting course.
Ostern said she was amazed by all the support she and the family had received both through Givealittle, where almost $24,000 was raised, and by the team working with Cooper to help him recover.
But most of all, Ostern said she was proud of how both her boys were handling the situation and amazed by Cooper's resilience and attitude towards life.
"I can't even believe anyone can think about living life how he is," she said. "He's really strong. He's an amazing, amazing young character."
Throughout it all, Cooper had done things his way, Ostern said.
Doctors did not think he would breathe on his own again, but he did. They thought he would need therapy to learn to speak again, he didn't.
The family was now working toward giving Cooper as much independence as possible, Ostern said.
"We're just focusing on doing things he loves to do. We're just so thankful to have Cooper. He's an amazing young guy. He's going to do amazing things. Watch this space."