He and the two women were allegedly shot and rushed to Auckland City Hospital with serious injures.
He heard a loud bang and collapsed on the ground, he told Feeney. He had no idea who the shooter was.
Feeney said the shooting was "totally random, he [Andersen] didn't even do anything, just happened to be there".
"He is really in a lot of pain and seems barely conscious," she told the Herald on Sunday.
"The doctors say he has more bullets [or] pellets in his body, but they are so tiny that it's hard to remove them all."
Feeney is unable to visit her brother in hospital because she is isolating at home with Covid-19.
In a post to Facebook, Feeney said her brother will be "very traumatised" by the incident.
A Givealittle page, set up by Andersen's friend Lockie Flynn, has raised almost $7000 to help keep Andersen's "business afloat" and rent paid while he recovers from "this horrendous incident".
"Two weeks ago today we stood at the altar with this man by our side as our bestman," Flynn wrote on the page.
"At 3am on Saturday morning, we answered the phone to 'I've been shot'."
Feeney said her brother owned a business, JDM Garage, where he fixed up and modified sports cars. He would have to keep paying rent on both his house and the garage - around $1600 a week - despite having no income while in hospital.
