Hughes, who played 26 Tests, was 25 years old when he died from bleeding on the brain in November 2014.
The family of Australian cricketer Phillip Hughes walked out of the inquest into his death on Friday, with his father calling the Sydney Cricket Ground an "unsafe workplace".
Hughes, who played 26 Tests, was 25 years old when he died from bleeding on the brain in November 2014 after being hit on the base of the skull by a ball during a domestic Sheffield Shield match in Sydney.
The five-day inquest, which wraps up Friday, has looked into whether he was targeted with short balls or "sledged" with unsettling comments from opponents, but has also exposed tensions between Hughes' family and the cricket community.
In a statement to the coroner, Hughes' father Greg wrote that he was concerned about the amount of short-pitch bowling to his son.
"By those balls not getting pulled up, of course this kept the bowlers continuing to target my son in an ungentlemanly way," he wrote in the undated letter.
Greg Hughes added that comments made by the opposing New South Wales bowlers "were more abusive and intimidating then sledging", raising the alleged "I'm going to kill you" remark that bowler Doug Bollinger has denied making.
"These slanderous comments ... and the use of illegal deliveries in my eyes lead to a very unsafe workplace," he said.
Under questioning earlier this week, Bollinger said he did not recall telling Hughes or his batting partner "I'm going to kill you", as suggested by counsel for Hughes' family Greg Melick.
Melick criticised the players' "failure to remember or admit", The Sydney Morning Herald reported.
"At the end of the day, there was a plan, there was sledging, and short-pitched balls were bowled at Phillip Hughes, which increased the risk of an injury," Melick said.
Hughes' parents and siblings walked out of the court in Sydney during closing comments by counsel representing Cricket Australia, Bruce Hodgkinson, who said players were honest in their testimonies to the inquest, the Herald reported.
Some family members also appeared distressed when counsel assisting the inquiry Kristina Stern advised coroner Michael Barnes not to make recommendations on sledging or style of play before Hughes was hit, the Australian Broadcasting Corporation said.
"It is abundantly clear that once the tragic accident had occurred, there was nothing that could have been done to prevent Phillip's death," she told the hearing.
Hughes' death stunned Australia and the world cricket community and sparked an outpouring of grief.
The coroner is examining the manner of his death and can make recommendations to improve safety, with his findings expected to be released in the coming weeks.
An independent review into the death, ordered by Cricket Australia, has already recommended that helmets be compulsory for batsmen and fielders near the wicket.