Kai Hao's parents moved to Melbourne to live with him but now they have to take him back to China in a box.
Gunman Yacqub Khayre shot and killed Chinese-born Mr Hao, held an escort hostage and injured three officers before dying in a hail of bullets in suburban Brighton on Monday night.
Mr Hao's distraught mother said the 36-year-old was her only son and they were relying on him to provide for them when they were old.
"I feel like my world has ended and I can't describe how sad I feel right now," she told reporters through an interpreter on Wednesday.
"When I sent my son to Australia I was happy to see him go to a new country and now I have to take him back to China in a box."
The distressed and tearful woman said she hated the man who killed her son.
"I have to say I hate that terrorist who has tore my family apart," she said.
"Now, I send him off to work one day and he never came back and I don't know what's going to happen."
The hotel receptionist arrived in Australia in 2002 and had studied at Monash University.
Mr Hao leaves behind a wife and child.
Somali-born Khayre was on a terror watch list and in a deradicalisation program when he shot Mr Hao dead in a Brighton apartment building and barricaded himself inside a room on Monday afternoon.
At 6pm, he left the building and fired at police, wounding three of them before they gunned him down.
Victoria Police is treating the attack as a terrorist incident.
It is understood Khayre was listed as a participant in the "community integrated support program" - a deradicalisation program run by the Islamic Council of Victoria and funded to take up to 22 people each year.
One Special Operations Group officer has shotgun pellets in his face and will need surgery, while another has had surgery for a serious injury to his hand.
The hostage, a 36-year-old woman, was tied up at one point during the siege, before she was rescued from the ground floor apartment.
Khayre once spent 16 months on remand before being acquitted of a 2009 terror plot to attack the Holsworthy army barracks in Sydney.
He was later jailed in 2012 over a violent home invasion and released in December.
Victoria's parole board chair, Judge Peter Couzens, said the board was not told Khayre was on any terror watch list or that he was any danger to the community or "it would have acted".
"We were not told anything along those lines either at the time of making the order or subsequently," Mr Couzens told 3AW on Wednesday.
Mr Couzens said such information should "absolutely" be shared with the parole board and Corrections Victoria.
Victorian Premier Daniel Andrews now wants spy agencies to make submissions to parole boards about inmates on terror watch lists.