Matthew Reynolds was "absolutely" not to blame for a Sydney Harbour boating tragedy, but is yet to reveal who was at the helm of the overcrowded runabout he took on an impromptu cruise, his father says.
About 2.40am (AEST) last Thursday, an ex-navy dive boat collided with a larger fishing boat, killing six people and injuring eight others, including Mr Reynolds.
Witnesses said the boat, licensed to carry just eight people, had set out from a Balmain wharf with 13 passengers and Mr Reynolds as skipper about an hour before the crash.
Police on Wednesday would not comment about the progress of their homicide investigation, but Mr Reynolds' solicitor Greg Walsh said he had advised his client against participating in a formal police interview until his condition improved.
While Mr Walsh said Mr Reynolds did pilot the boat away from Balmain's Darling Street wharf, he would not say who was at the controls at the time of the collision at Bradley's Head.
He said releasing that information had "legal implications".
"I'm not suggesting he wasn't in command of the vessel (but) he wasn't driving at the time of the collision," Mr Walsh told AAP.
Sydney Ship Repair and Engineering said again on Wednesday that Mr Reynolds had taken its runabout without its knowledge or authorisation.
"This vessel is a work boat and is only used by the company to transport workers to and from our facility during daylight hours," company managing director John McPherson said in a statement.
"Despite media reports to the contrary, Matthew Reynolds was not authorised to use the boat."
The company described Mr Reynolds as a former contractor who was related to a current employee.
Mr Walsh said Mr Reynolds did not steal the boat.
"I'm not suggesting that the owners of the boat gave him permission to be using it at that particular time of night, it's a grey area, but I believe it's a lot to do with a standing agreement between the company and Matthew," he said.
Mr Reynolds, 31, remains in Sydney's Royal North Shore Hospital (RNSH) in a stable condition with multiple spinal fractures.
Outside the hospital, Charlie Reynolds defended his son, saying he believed he was "absolutely" not to blame for the tragedy.
"I know Matt. He's an honest and hardworking guy and very capable person, very capable," he told reporters.
He said his son had told him "he wasn't behind (the wheel of) the boat" at the time of the crash.
"His condition is improving very slowly, he's got a long way to go though, both physically and mentally."
Mr Walsh said his client had been cooperating with police, despite refusing to be interviewed "on my advice".
"Police just wanted to take some photos of his injuries and a ... swab for DNA ... that's fine," he said.
"We are cooperating with police but you can't subject someone who is in pain to further stress."
Mr Reynolds is expected to be released from hospital in the next couple of days.
Alex Rumiz, 22; Stacey Wright, 21; Elizabeth "Lizzie" Holder, 20; Ashlei Ayres, 32, and Jessica Savanna Holloway, 25, were killed in the harbour collision.
One of those rescued - Alex Nikakis, 29 - died later in hospital from severe brain injuries.
A funeral will be held Thursday for Balmain barmaid and hairdresser Elizabeth Holder at 11.30am at the Camellia Chapel of Macquarie Park Crematorium, at North Ryde.
