Billy Joe Saunders has warned that his friend and heavyweight champion Tyson Fury could "sink into the soil" if he is stripped of his boxing licence.
"He has been brought up since a young kid doing this," boxer Saunders told the Victoria Derbyshire programme.
"If you take it away from him, he will not look for a daily job in Tesco's."
At a meeting on Wednesday, the British Boxing Board of Control will discuss Fury's admission that he had recently taken a large quantity of cocaine.
Fury told Rolling Stone magazine earlier this month that his use of the drug is a consequence of depression that has been exacerbated by abuse he receives for his cultural and religious background.
WBO middleweight champion Saunders, who, like Fury, is from a Traveller background, says the 28-year-old only knows boxing.
"It is a big mistake, taking his boxing licence away. It is like taking food from a baby," he added. "He needs the licence to pull through."
In the wake of Fury withdrawing from a rematch with Wladimir Klitschko in October, the World Boxing Organisation set him a 20 October deadline to state his case for keeping their version of the heavyweight crown.
The World Boxing Association president, Gilberto Mendoza, has said Fury could be stripped of their title as well.
Peter Fury, Tyson's uncle and trainer, has said his nephew is prepared to relinquish both belts and could return to training by March 2017.
Fury has not fought since beating Klitschko last November and is facing a UK Anti-Doping hearing next month with reports claiming he tested positive for banned substance nandrolone in February 2015.
He was filmed cheerfully buying drinks for England fans in Nice during Euro 2016, in the wake of pulling out of a previously scheduled rematch with Klitschko with an ankle injury.
But Saunders says Fury is using drink and drugs in an attempt to control a darker part of his personality.
"People say he has done this because he wanted a good time," he said.
"You are not going to walk away from £6m to £10m [Fury's expected purse for a rematch with Klitschko] for something stupid, for one night. It is bad depression."