Dr Blake said he, his wife, and their four sons offered their prayers and condolences to the families of the men who died in the accident, and described his son's survival as a miracle.
He said he was very grateful for the people and emergency services who rescued and treated his son at the scene and to all the medical staff, doctors and nurses, at Waikato Hospital.
"They were all very professional. The care he is receiving is appropriate and I have been impressed by that," he said.
Police said the Holden Commodore the five men were in was overtaking in a dip in the road, just north of the Makatote Viaduct, when a truck and trailer came around a corner from the opposite direction.
The Westpac Waikato air ambulance attended the accident and transferred Mr Blake to Waikato Hospital.
Inspector Steve Mastrovich said the car "smacked head-on into the truck and trailer".
Any prudent driver would not have overtaken another vehicle along that section of road, he said.
He said the tourists were driving in different circumstances to what they would have been used to.
The tow truck driver who attended the crash last night, Colin Fredricksen, told APNZ it was one of the worst crashes he had seen on the job."I've seen others that have been bad, but not so many people involved."