When his mother answered the door she tried to keep Forman out, but he forced his way in.
"You brandished the machete, holding it in an elevated position," the judge said.
The victim retreated through the house, closing a set of French doors as he went. He ran out another side of the house to call for help.
Forman "shoulder barged" his way through the doors, smashing the glass panes. He then shoulder barged into a workshop on the property and began hitting the bonnet of his mother's car with the machete. He came back to the house and used the machete to smash seven glass windows.
He has pleaded guilty to possessing an offensive weapon, threatening to kill, wilful damage, and two further charges of threatening to kill and driving with excess breath alcohol.
The latter charges relate to an incident in September when Forman called his brother and said that the victim should have his head cut off.
"You went on to say that someone was going to die," the judge said.
The following day he was caught driving with 447mcg of alcohol on his breath. The legal limit is 250mcg.
According to victim impact statements, Forman's mother said the effect of his offending had been "devastating" on the family.
His stepfather "lives in constant fear that you will act out in a similar way again", and felt Forman had no remorse.
A clinical psychologist's report said Forman had complex post-traumatic stress disorder, but the judge said it was difficult to figure out the cause.
The judge said the offending could have ended much worse if Forman had actually managed to kill the victim.
"If that had happened you would not be before me today, you would be in the High Court facing either a charge of murder or manslaughter, and then the only question would be how many years imprisonment you would have received.
"That is why the court takes threats to kill and threats with the presence of weapons seriously."
He sentenced Forman to eight months of home detention with six months post-detention conditions, and judicial monitoring for the duration of the sentence.
He also disqualified Forman from driving for 13 months, put a protection order in place, and ordered he make a reparation payment of $3286.