On Tuesday, the boy pleaded not guilty to manslaughter and possession of a prohibited firearm. His 16-year-old brother died from a gunshot wound to the head at the family's Dorval home.
The 12-year-old remained expressionless during his court hearing Friday in Montreal youth court.
His defence lawyer has requested psychological support for the boy, who will attend a bail hearing scheduled for 10 a.m. ET Tuesday.
The viewing and funeral for the 16-year-old are planned for next Wednesday and Thursday.
According to his lawyer, the boy has only met with a nurse since he was taken into custody at a youth detention centre this week.
The judge agreed to remand him into the custody of youth protection to allow him access to psychological support.
The identity of the accused and the victim cannot be revealed under the Youth Criminal Justice Act because they are minors.
The father of the accused was charged in the past for assault, death threats and negligent use of a firearm. The case was settled in 2008 by a court order to keep the peace.