Visal Chand also implored local authorities to do all they could to improve intersection safety.
Conditions at the intersection of the fatal crash as well as the presence and quality of road markings and signage will be part of the police investigation.
Visal Chand hoped his brother's death would push councils and roading authorities to enhance safety features at rural intersections where needed.
"It's truly heartbreaking to see poor road marks and signs on rural roads," he said.
"It claims so many lives … please do something about it - upgrade signs and check for any improvements necessary at least to prevent accidents."
One of the other victims, Campbell, had an intellectual disability and had been supported by Idea Services for many years, Stuff reported.
He had been "incredibly excited" about his trip to the South Island to attend the Gold Guitar Awards music festival in Gore.
Idea Services Counties area manager Angie Kumar said Campbell was "well-liked among his friends and our staff".
"He always enjoyed holidays locally and abroad, and he was incredibly excited to go on this trip down south – we are very sad to lose our friend," he told Stuff.
"We all extend our deepest sympathies to his family, friends and many of our staff who knew him well and supported him in Auckland."
