Not knowing if Joshua had been involved, the family instinctively headed towards Nelson Hospital.
Their fears were confirmed on the way, MacLean told the Herald.
"We just slowly got snippets of messages coming through and then the fire service spoke to us."
The doctors "nearly lost him" that night because he was bleeding so much, MacLean said.
"He was pouring blood out."
Once he was stable enough to fly, Joshua was flown to Christchurch Hospital where he's still in an induced coma and will undergo numerous surgeries over the coming weeks.
His parents are staying with him in Christchurch and are being supported by Ronald McDonald House.
MacLean is trying not to think about how Josh got hurt, but said "kids at that age after a funeral, don't really think straight".
"Why would you be on the bonnet of the car driving? He wasn't that sort of person."
Instead the family is focusing on his recovery.
"Finding out is the least of my worries. What's happened has happened - you can sort anything out because you can't fix it now. All you can hope for is that they've learnt something.
"You can tell them until you're black and blue but until something's happened, they're not going to listen."
Joshua's cousin in Australia, Amanda Henderson, set up a Givealittle page to raise money for the family because being away from their orchard at a critical time during the season would put a "huge financial stress" on them.
In less than 24 hours, more than $5,000 was raised by more than 70 donors.
"Those who know Josh know he is such an adventurous and fun-loving guy who loves hunting and the outdoors," the page said.
"He is a promising competitive motocross rider and junior South Island champion. We do not know if he will be able to ride again."
MacLean said it was a real comfort to know they're supported by their community.
