The janitors' sentences were delivered on the day before Neil Bantleman's trial was set to begin in Jakarta.
"We've got to ensure that we continue to fight the fight and make sure that Neil gets his due process but it is very concerning that a trial that was run along similar lines has this outcome," Bantleman's brother, Guy Bantleman, said in an interview with CHCH News in Hamilton, Ont.
"The continued lack of evidence, both physical and medical, really does question how this decision was made and does raise into question if Neil will get a fair trial at the end of the day."
The janitors contracted to work at the Jakarta International School were arrested in April following reports from parents of a six-year-old boy who claimed to have been sodomized. Police said a sixth suspect committed suicide while in custody after drinking bathroom cleanser.
In their separate verdicts, judges at the South Jakarta District Court concluded that all the defendants were guilty of violating the country's Child Protection Law and Criminal Code.
Four male defendants were sentenced to eight years, while the only woman in the case received seven years as an accomplice. All the defendants were also fined to pay $8,000 respectively or serve three more months in jail.
Their lawyers contended that the evidence was weak since medical reports found the boy had no major injuries or abnormalities. Prosecutors said the boy had been sodomized up to 13 times.
"The verdicts were unfair," said Patra M. Zein, one of the lawyers. "We will appeal, and hopefully we will get justice from the higher courts."
Bantleman and an Indonesian teaching assistant, Ferdinant Tjiong, are also accused of sexually abusing the boy and two other students, and have been in custody since July.
Both men have maintained their innocence. The school's principal and a number of fellow teachers also say the two are innocent.
"Neil has gone through several milestones and obviously we've not got a positive result at any of those milestones," Bantleman's brother said.
"He is continuing to be strong but he's got to be disheartened that even though he is completely innocent of these alleged crimes, we're not getting that message across either to the prosecutor or to this point the courts."
Bantleman's family expects his trial to hear statements from the alleged victim and the victim's mother, and also expects a discussion on the medical tests used in the case.
They are also calling on the Canadian government to publicly declare its support for Bantleman as he heads into what's expected to be a lengthy trial.
"It's been a long six months to get to this point and it's going to be a long several more months but we've got to continue to make everyone aware of this case," Bantleman's brother said.
"We've got to really elicit the help of the Canadian government. This is the time they really need to step up given the negative outcome on the janitors trial."
The family has received a letter from the junior federal minister responsible for consular affairs, stating Ottawa won't pressure Indonesia to release Bantleman from jail.
Both Bantleman and Tjiong could face up to 15 years in prison if convicted.
— with files from the Associated Press.