Brasher played with Jack's father Josh Bostock, also a winger, at Balmain in 1997 and recalled how he was blown away by Jack's talents when he watched him play.
"Josh took me down to watch Jack play when he was a kid at a rep trial at Cronulla. I admired his athleticism for a kid that age and he had a lot of skill to go with it," Brasher told AAP.
Brasher played against former South Sydney forward Paul Sutton in 1997 before becoming a Rabbitoh himself the following year.
Sutton became a player manager post-career so Brasher called him about the 19-year-old Bostock, who he now manages, after watching him trial.
"Brash' just rang me up and said, 'I've got a young kid for you' and it all went from there," Sutton told AAP.
The 193cm Bostock is an Illawarra junior and represented NSW Under 19s last year before joining the Dolphins.
"Jack has got a bit more skill than his dad but they are both big, tall guys," Brasher said.
"Jack has also got speed. He has got the whole game really and as he matures and gets even bigger I think he could turn into a weapon.
"I haven't seen his whole rise but I am glad he went up to the Dolphins, played a trial and now he's got picked in first grade. It is a great thing for him and his family."
In a remarkable twist Brasher also played with Jason Teague, the father of Dolphins rookie forward Mason Teague who has also made his NRL debut for the Dolphins
"His dad and I played juniors together, and against each other, in Harold Mathews and SG Ball at Western Suburbs and then I brought him over to Balmain where he made our reserve grade team," Brasher recalled.
"Now his son Mason is playing in that Dolphins team and it is good to see him doing such a great job. It's magnificent I've got two old friends' boys in that same team."
Brasher said Dolphins coach Wayne Bennett was the right man to coach the rookies.
"Before my last Test matches for Australia (in 1998) I wasn't going to be in the team but we had a training camp for the guys that weren't in the semi-finals and Wayne asked trainer Billy Johnstone who amongst the players was training hard," Brasher recalled.
"I had trained my butt off in that camp and Wayne gave me my last chance to play for Australia because of how I trained and my attitude.
"That's how he is with these young kids at the Dolphins. Wayne would see them training their butts off in pre-season and is willing to give them a go. He will reward hard work."
