He was diagnosed with a grade four glioblastoma, which is an aggressive type of brain tumour more common in men aged over 50. A further operation was carried out in Leeds.
The Meltham event originally began as a meeting of a few Subaru enthusiasts.
Connor and his dad Scott are huge fans of Subarus and other rally-based road cars.
But following Scott’s appeal on ScoobyNet Subaru forum, news about the event has exploded online, turning a modest motoring meet into a feast of fast car fun.
The appeal has also spread among the online motoring community worldwide, garnering hundreds of thousands of views.
So far some 800 car enthusiasts have now pledged to bring their exotic automobiles, including American rally driver and Gumball 3000 veteran Alex Roy, who’ll be arriving in a rare Morgan three-wheeler.
Connor’s grandma, Amanda Harrison, said: “It started off as just 20 cars. We just wanted to get a few cars there and it developed from that.
“We’re just getting a bit worried if there’ll be enough space!”