The 32-year-old Preston man was shot by police and remains in hospital, and was charged on Friday after the incident at a Hillside home a week earlier.
A 61-year-old, believed to be the man's stepfather, was found on the lawn with critical injuries and could not be revived.
The dead man's stepson moved towards officers armed with an edged weapon despite requests to drop it, Victoria Police Detective Inspector Dean Thomas said.
An officer fired one shot inside the house before the armed man went outside and stabbed a police vehicle's tyre, police allege.
The man again moved towards police who fired several shots, Det Insp Thomas said.
He was hit in the lower body and remains in hospital, with a bedside remand hearing expected on Friday afternoon.
The stepson was known to police prior to what detectives were treating as a family violence incident, Det Insp Thomas said.
A heavily pregnant 27-year-old woman, who police believe to be the alleged offender's sister, was home at the time and ran from the house.
She was uninjured but taken to hospital for observation.
The armed crime squad and professional standards command will probe the shooting, which is standard practice when officers fire their guns.
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