She was due to start at the University of Auckland. The family had come to New Zealand to help her settle into her new home before they returned to Hong Kong.
Mr Dahm said today he would like to see stricter regulations for tourist drivers and improved road infrastructure.
"It's not his fault, so I'm happy just to pay him to stay at home and get his head sorted out, go on a holiday, just get over it and come back when he's ready.
"He's a real good driver, so I don't want to lose him, and with the shortage [of truck drivers] around the whole country ... you don't want to lose the ones you've got."
Mr Dahm said of the crash: "So often it's the innocent people that end up getting killed, and the people that have caused the accident get away scot-free, like drink-drivers and all that. But this time, it's the guilty people that are paying the price, and they've paid the ultimate price.
"I said to him [the driver], 'That could have been your wife or kids, or that could have been my kids, or anyone's kids coming there the other way, or even yourself in a car, imagine how that would have gone?' It's not nice to say, but that's just how it is."
The driver told Mr Dahm the Lees' car turned a corner on to the road in front of him.
"He was in his left lane going up towards a left-hand corner for him to go around, and the car comes around the corner, right there, right on the wrong side of the road," he said.
"As soon as it came around the corner and seen the truck, which is only 20m or 50m away from it, it just swerved around. They must have maybe realised and they swerved around to try to get on their side, and hit the truck right on the centre of the truck."
Because the car swerved, it hit the truck at an angle.
"That's all that would have saved the person on the left-hand front seat was the fact that the car was turning left trying to get back into their own lane where they should have been," he said, referring to Mr and Mrs Lee's son who was the front-seat passenger and the only person in the car to survive the crash.
"Our driver said they were just about on the metal on his far left, so as far on the wrong side of the road as you could possibly be. And as soon as they seen him coming they must have realised, but of course it's all too late then."
The truck was initially impounded by police for inspection, and had just been released, Mr Dahm said, adding "there was no issues there, no issues with the driver".
He called for better infrastructure on state highways, particularly median barriers on windy main roads.
"It's ludicrous the money we all pay for roads, and some of these cases could be prevented by that [median barriers]."
He also called for tighter regulations for tourist drivers and rental car companies, particularly for motorists who come from countries where people drive on the right-hand side.
Yesterday, assistant commissioner of road policing Dave Cliff said "a small number" - around 4.5 per cent - of crashes in New Zealand involved drivers on an overseas licence, with four fatal crashes this year involving such drivers.
A project is currently running in the Queenstown Lakes district using steering wheel tags with safety messages in rental vehicles.
