Emmeline McKinnon said she was worried about her mother, who was widowed when their father died in tragic circumstances when they were younger.
Emmeline, who works in law enforcement in Australia, said Sean looked the most like his father and the family didn't know how his death would effect their mother, who remained in Australia.
The 39-year-old described her brother as a wonderful person.
"We love him very deeply. We were devastated to hear that his life had been taken from him," she said.
"We just don't even know how to begin to put life together.
"The worst thing was telling my mother. I think he was my Mum's favourite.
"We're just going to miss him a lot. He'll be missed around the Christmas table."
She described her brother as loving to travel and remembers the last time she spoke to him was when she helped him get a new passport.
"Oddly enough I said a goodbye that I would say if I knew I wasn't going to see him again."
Emmeline said Sean loved being in New Zealand to visit his fiancée, Canadian midwife Bianca Buckley, when he was between jobs in Australia.
"He loved the surf here. He loved the lifestyle and the place."
The couple had not set a date yet for their wedding.
She described the couple as having been young and free.
"They're young. They're still at that great age where that reckless temperance of youth hasn't come into line with the responsibilities of adulthood and it never will for Sean now."
Emmeline said Buckley, who was not at court, was resilient and strong.
"I cannot even begin to understand what she's gone through. She's a really strong young woman," she said.
The family had been supporting Buckley, who was now their priority, she said.
"We're just really glad she's alive."
Emmeline said being in court today was important.
"I just didn't want Sean to just be a face. He has a family. He's very well loved. He's a real character."
McKinnon was supported by her younger brother Lachlan, and sister Mary McKinnon.
The family wanted to understand the process and were grateful of the support the community had shown them including New Zealand police, Air New Zealand and the court.
She said they had been prepared to come to New Zealand "angry" but have been shown overwhelming support for which they are very grateful for.
She had never been to New Zealand and said the way the community had reached out to them as complete strangers, she had never experienced before.
"We are deeply grateful for the compassion expressed by people in the New Zealand community."
The siblings did not know how long they would stay in New Zealand but wanted to wait for the release of their brother's body so they could take him home to bury him.
Detective Inspector Graham Pitkethley said information from the public had contributed to finding the alleged offender.
Pitkethley confirmed the dead man was Sean McKinnon, 33. The police were supporting the family.
"I know this has been a shocking event for the community," he said, thanking those who had responded to the media appeal yesterday.
"This has shocked and touched a number of people in the community and the inquiry team as well."
The investigation was continuing and a post-mortem was being carried out.
No one else was being sought at this point over the tragedy, Pitkethley said. The incident was a "random, tragic event".
All Pitkethley was willing to say about the alleged offender was that he was a Waikato local.
Some members of McKinnon's family had arrived in New Zealand and were speaking with police, he said.
The family were traumatised, he said.
Witnesses had come forward to help police find the man, he said.
"I want to thank those in our community who contacted police with information and assisted us with our investigation," he said.
"I also want to acknowledge the hard work from the investigators involved in this case.
"It is because of their dedicated efforts and the assistance from the public that police were able to make an arrest within 24 hours."
In response to an Australian journalist's question about whether tourists should be concerned that this was a "wider issue", Pitkethley pointed out the high level of media interest suggested the shooting was a "random and unusual" event.
McKinnon's partner, Bianca Buckley, a midwife at Counties Manukau DHB, ran two kilometres on a dark, rugged road to find help after she watched in horror as her fiance was shot.
McKinnon, 33, grew up around Warrnambool in Victoria's southwest. The pair got engaged around Christmas 2017, according to their social media.