Mrs Cooper, who will support the Wallabies on Sunday, still lives at the tidy Kaikohe home where Quade spent much of his childhood.
Pictures of the whanau are everywhere, but pride of place in Mrs Cooper's living room is an action photo of her grandson in the yellow jersey, about to offload.
On the opposite wall is a photo of Quade and teammates with the Queen, taken a few years ago at Buckingham Palace.
"He's a good boy. I suppose all grandmothers say that," she said.
"May the best team win. If the Wallabies don't win, it's not the end of the world. It's just another game.
"I just want people bad-mouthing him to leave him alone ... that's all out of jealousy to him."
Kaikohe Bowling Club president Dion Davis said the bowlers supported Mrs Cooper and her grandson but would remain loyal to the ABs.
A great aunt of Cooper, who lives in Kaikohe, can't pick a clear winner for the epic clash but is likely to tilt towards the ABs.
"He's a nice boy, not arrogant," she said.