A Melbourne woman who teamed up with her daughter and others to torture a man, which included carving "dog" into his forehead and hacking him with a meat cleaver, has been jailed.

Lorraine Howard, 44, was one of a group of drug addicts who brutally tortured the man, wrongly believing he had stolen cash and jewellery from her Cranbourne home.

Victorian County Court Judge Christopher Ryan described the man's attackers as vigilantes operating in the "milieu of the drug world".

He said while Howard did not strike a blow against the man, she was present and complicit in the torture session, which left the man with a permanent brain injury.

The man was bound, beaten, slashed and stabbed with knives, spat on, hacked at with a cleaver and set alight by the group, which included Howard, her partner and her 20-year-old daughter.

As the group interrogated the man about a burglary he did not commit, they also threatened to slice his genitals and carved the word "dog" into his forehead.

Howard later told police that during the assault, her partner had kicked the man's head "like he was kicking a football".

On Friday, Judge Ryan jailed Howard for two years and six months, saying he would have imprisoned her for seven years had she not pleaded guilty and agreed to give evidence against her co-accused.

The group dumped the man at his parents' house after the March 2012 attack and Judge Ryan said they would be forever traumatised by memories of finding their son drenched in blood.

"They now live a nightmare," he said.

"He will live the rest of his life reminded of your offending against him, as will his parents."

Judge Ryan said the man now suffered from depression and a brain injury.

He said Howard's drug problems stretched back to the age of 12, and were behind her 140 prior court convictions.

Howard must serve a minimum 18 months before she is eligible for parole.