He was also suffering from hypothermia.
Paramedics worked for an hour to save him but he died at the scene, said a spokeswoman for the rescue service.
Mr Andrews' brother, Douglas, phoned Ms Imam-Emery on Monday asking if she had heard from the man, but she had not.
"So I gave him the next door neighbour's phone number to see if his car was still there and when she last saw him. It's all very tragic."
It was understood Douglas Andrews had been notified by someone at his brother's workplace, an office in Otahuhu, when he did not show up on Monday.
The neighbour had seen Mr Andrews walking on Saturday afternoon, but it was 5pm on Monday before police - alerted by a very concerned Douglas Andrews - arrived at the bach looking for him.
"They found him at the bottom of the stairs and they did everything they could. It is such a horrible thing, obviously they tried to get him but they couldn't," said Ms Imam-Emery.
"If only we'd known a little earlier, we might have been able to save him, it's so tragic."
St John spokesman Robbie Walker said an ambulance arrived at the scene at 5.08pm, and the rescue helicopter at 5.35pm.
Mr Andrews' brothers, Douglas and John, were too upset to speak to the Herald yesterday but said the accident had been very distressing for the family.
Ms Imam-Emery said Mr Andrews was a lovely man, who she met through her work as a physiotherapist in South Auckland, where he sought treatment for a back problem.
"Once a year for the last four or five years he hired the house for a week ... he loves it down there. He loves walking and was very active.
"He was fantastic, very friendly, very helpful - he would do anything for you. I've known him for years, it's very unfortunate."
He had recovered from a bad spinal condition, which had propelled him into the outdoors.
"When I first saw him he was folded over, but he made great progress and then when I closed my clinic he used to take himself to the pool and do his exercises there.
"He was very active, he did everything."
Mr Andrews' death has been referred to the coroner.