His mother, sister and partner were by his side last night. His stepfather, Bruce Cawley, described his condition as "50:50".
Emergency services were alerted to the accident by a whitebaiter on the south side, and without him, Andrew would still be missing, his stepfather said.
"I don't know who he was ...
"I hope the guy would like to get in touch with us to thank him.
"I'm just so, so thankful to the emergency services, too. They do a marvellous job."
The fact he was wearing a lifejacket, a gift from his stepfather, made the difference, Cawley, who was a firm believer in taking safety precautions, said.
"It doesn't matter whether you're my age, his age, or a young kid — it's just a safety thing.
"[Without it] the water would have taken him under and they would still be out there searching."
Waitaki River was Andrew's favourite whitebaiting spot. He caught 32kg last weekend, and the 15-year veteran fisherman knew the spot "very well".
Cawley described his stepson as a down-to-earth man, and said his 2-year-old daughter was the "sparkle of his life".
The incident comes after a whitebaiter in the same area survived after being swept out to sea three weeks ago.
The man was wearing a lifejacket and made it back to shore unaided.