The tiny sock fell from little Aarush's foot as rescue workers tried to resuscitate him. It now rests in Macwan's pocket.
"I can feel he is here forever," he told the Weekend Herald.
The 32-year-old wiped tears from his eyes yesterday as Judge Charles Blackie, in the Manukau District Court, discharged him without conviction.
Aarush drowned after the van he was strapped into rolled over a bank and landed in Lake Dunstan near Cromwell during a family holiday in April.
Macwan, who had left the handbrake off, was charged with careless driving causing death.
His wife, sister-in-law and her children were able to escape, but it was over 40 minutes before Aarush's body was brought to the surface.
Judge Blackie told Macwan he was fully aware of what he had been through. The judge agreed with Macwan's lawyer, Frank Pereira, who described the incident as momentary inattention.
After the verdict, Macwan rushed from the dock, embraced his wife, Kinnary, in the public gallery and the two hugged and wept.
But despite the verdict, Macwan cannot forgive himself.
"It is a life sentence."
The memories came flooding back as the judge told the court how the family pulled over for a break beside Lake Dunstan on April 21. Moments after parking the van, Macwan heard screams and turned to see the Toyota Hiace rolling towards Lake Dunstan.
He ran and tried to push the van away from the lake but it had rolled into the water with his wife, sister-in-law and Aarush trapped inside.
"I was in tears remembering. It is every day... I'm already in hell, my personal hell."
Mr Pereira told the court Macwan was used to automatic vehicles, in which putting the handbrake on was not as important as in a manual vehicle. The van had not started moving until some time after Macwan walked away.
Judge Blackie agreed a discharge without conviction was appropriate.
Police did not oppose the application. Sergeant Eardley Dijkstra said the case was tragic and the decision to prosecute was not made lightly: "Police took into account that a death had occurred."
Judge Blackie commended the police for bringing the matter to court.
"There was a loss of life here and the police have a duty to investigate loss of life and they certainly have a duty to bring it to court."
Macwan now hopes to gain permanent residency in New Zealand so he can remain close to his son's grave.
Strangers had called him to offer support and Victim Support had been "fantastic" and he now planned to become a social worker and "to give back the love", Macwan said.
"I told my wife that I might be born in India but today I am a New Zealander because of the way they accept me and show their love. It is remarkable; they accept me as one of their own."
