"He taught me to be positive, be tough and never give up like he never gave up," Jaden said.
"I'm really sad [that he has passed away] because I won't be able to see him again and talk like we used to talk."
Bay of Plenty teenager Matthew Bindon, aged 15, met Lomu through the Kidney Kids NZ charity, for which the rugby star was a patron.
Bindon, who was born with only one functioning kidney, said meeting Lomu a couple of years ago had been inspiring.
"You could feel the energy around him - he was such a vibrant person. There was something about him that was really lovable.
"It really touched me that he spent time with me. He's a great person who's gone now and who has done so much for us."
Kidney Kids NZ chief executive Keith Mackenzie said the organisation couldn't have asked for a better patron than Lomu.
"I think the important thing was the kids knew that he had experienced kidney disease -he had gone through the trials of dialysis, he'd had a transplant - so from their point of view it was reassuring for them to have somebody like Jonah to talk to," he said.
"They were blown away by the fact that he was prepared to come along, sit down, talk and just be one-on-one with them."
For more information about Kidney Kids, visit www.kidneykids.org.nz