"That, in effect, was his security blanket."
Mr Earwaker said Haiu had been due to receive a prognosis on his cancer the day after the assault took place.
He said Haiu had lost between $400,000 and $500,000 in property deals with Mr Cooper, whom he had tried to contact without success.
"He had concern for his family."
When Haiu met Mr Cooper, he threw two punches. Mr Earwaker said one was a "glancing blow and the other was a full blow".
"I would put the offending at the lower end of the scale."
He said Haiu realised it was wrong and left Mr Cooper's home at once.
Mr Earwaker said a conviction would be out of proportion to the gravity of the assault.
He said there was little chance of recovering the money.
Mr Earwaker said Haiu was now focusing on his health and was waiting for the results of further tests.
"It seems the tumour has decreased in size but it is still far too early to tell."
The defence lawyer said Haiu would be willing to do some form of voluntary community service.
Police did not oppose the application but prosecutor Geoffrey Bardsley said Mr Cooper wanted some form of punishment.
"He indicated he did not wish to stand in the way of the defendant's career and overseas travel."
Judge Gerard Winter reserved his decision, and Haiu is due back in court next month.
Outside court, Haiu said he had not had chemotherapy for a few weeks and was feeling better. "I want to still play rugby, no matter what happens, because that is my passion."
When Haiu was asked about the money he had lost, his manager, Bruce Sharrock, cut in and said, "Things are under way", but would not comment further.
The Auckland lock, who has played 53 games for the Blues and 75 for his provincial team, was diagnosed with bone cancer in April and has been on indefinite leave from rugby.