“I had never come across anyone who didn’t admire Machar,” Ms Kot, 19, said on Wednesday.
“He was always smiling, telling jokes, telling stories and had the most goofiest, contagious laugh.”
She said her brother grew up playing soccer and enjoyed hanging out with his friends and family.
“He had such a unique personality, even to people who he only met a few times, he had a lasting positive impact on their life. He always went out of his way to make others happy. He was well and truly the life of the party.”
Mr Kot’s father said the loss of his son was hurting their family and the wider South Sudanese community.
“He was a big leader in the community as well as the family. He was a role model,” he told the Seven Network on Wednesday.
Mr Kot’s father said he told his children to mourn for their brother peacefully because “we don’t want any chaos in our community”.
Mr Kot’s death was the second fatal stabbing in Melbourne in less than a week, after 15-year-old Solomone Taufeulungaki died after a knife attack at Deer Park on June 16.
Seven boys between the ages of 13 and 16 have been charged with affray after they allegedly set upon Solomone after school with knives and baseball bats, but no one has yet been charged directly with his death.
North West Metro commander Tim Hansen last week raised concerns about the rise in knife crime in Melbourne.
“It’s a real concern of mine as I look out across Melbourne … I see the risk this is presenting,” he said.
“It’s time for us to collectively say enough is enough. These attacks are killing our young people, killing our teenagers.”
Police believe Mr Kot and Mr Deng were known to each other.
The investigation into Mr Kot’s death is ongoing.
Mr Deng has been remanded in custody to appear in Melbourne Magistrates’ Court on Friday.
Anyone with information is asked to contact Crime Stoppers on 1800 333 000 or submit a confidential crime report at www.crimestoppersvic.com.au
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Rachael Dexter is a breaking news reporter at The Age.
Simone is a crime reporter for The Age. Most recently she covered breaking news for The Age, and before that for The Australian in Melbourne.