A Japanese boxer is retiring to support his brother who has been in a coma since a bout in May, as the sport in the country reels from the deaths of two fighters.

Former WBC strawweight champion Yudai Shigeoka’s brother Ginjiro collapsed after a fight in Osaka three months ago and underwent emergency brain surgery.

READ: Ginjiro Shigeoka stretchered off after loss to Pedro Taduran

The 25-year-old remains in a coma but is no longer in a life-threatening condition, the Japan Boxing Commission says.

Ginjiro, a former IBF champion at the same weight who has a professional win-loss record of 11-2, was recently transferred to another hospital.

“I encourage him every day, telling him not to give up and to do his best, so that the flame in his heart does not go out,” Yudai, 28, said in an Instagram post on Wednesday.

READ: Two Japanese boxers die from brain injuries in separate bouts

“I believe it is my role as his older brother to enrich his life from now on.”

“Plans are progressing steadily. That is why I have decided to retire. I have no regrets. The real challenge begins from here on out,” added Yudai, who has a 9-2 record.

Japanese boxing is under the spotlight after super featherweight Shigetoshi Kotari and lightweight Hiromasa Urakawa, both 28, died days after injuries they sustained in separate bouts in Tokyo on August 2.

READ: Japan boxing to hold emergency meeting following deaths

Japanese boxing officials held an emergency meeting this week and vowed to introduce new safety rules.

New measures to be implemented as soon as possible include urine tests for measuring dehydration and stricter rules on boxers’ rapid weight loss, said Tsuyoshi Yasukochi, secretary-general of the JBC.

Ambulances will also be required on site, even for non-world championship bouts, something which is common practice in some other countries.