The man he helped, university student Don Prawinmet, returned shortly after the scuffle and opened fire indiscriminately at patrons, wounding three people.
But nearly a year after the shooting and four months after he was released from hospital, Mr Brown is being forced to live off a dwindling supply of donated funds as he becomes increasingly frustrated in his fight for justice.
As his medical bills mount, the compensation promised to him by the shooter's family has failed to materialise, and criminal proceedings against Mr Don have made little progress.
Mr Brown said he desperately wants to return home to Vancouver, Canada, but is reluctant to leave Thailand before justice is served.
“I am in pain every day," he said. "The doctors have said I will not walk again. I was here in hospital for six months because of a pressure sore, an ulcer that developed on my back from lying still for so long.
“I also have nightmares that he will come back to shoot me.”
Mr Brown, who worked as a teacher and freelance journalist before the shooting, said he was attempting to prevent Mr Don from being assaulted at the bar on Nimmanhemin Road.
“I was out with my girlfriend and three friends at the Ban Dain Bar, and Don came to our table and attempted to join us,” Mr Brown recalled.
“He was acting inappropriately with my friends and girlfriend, and at one point he touched the waitress' behind and she was the girlfriend of Morris, the bartender.”
Soon after that, a fight broke out. Mr Don was beaten badly, and Mr Brown and his friends helped escort him outside to safety.
“He returned while we were outside and going to leave ourselves and fired his gun five times. He hit three of us: Morris, a Korean student, and myself.”
A bullet stuck Mr Brown in the back, shattering his ribs and sending bone fragments into his spine.
“I need proper treatment at home in Canada, but I am afraid to leave Thailand before I receive compensation," he said.
"The treatment here is good but better in Canada. Here it is very hard to go around, there is a lack of accessible streets and transportation for wheelchairs."
Mr Brown said the shooter's family had paid some of his hospital bills, but have so far failed to deliver on a promise of 3.5 million baht in compensation.
“At first they offered one million, but they have not paid me and they have delayed this payment. I fear they will wait until after one year to pay me. They may fear I will launch a civil suit, which I cannot do after one year.”
The delayed payment and stalling criminal case against Mr Don have left Mr Brown fearing that justice may not be served.
Pol Col Dundecha Archawasamit, former superintendent of Puping police station, said the case has already been passed over to prosecutors, but could not give any indication of when it would go to court.
“We sent the case across late last year and it is now with the judge to gather the necessary documents,” he said.
“[Mr Don] confessed as soon as he was arrested that it was him who shot those people, but says he was very drunk and does not remember much.”
Pol Col Dundecha said the suspect was bailed on a 500,000-baht bond as the family took him for a mental health assessment.
“If he has a mental illness, it will probably affect the case. However, this is up to the court to consider,” he said.
Doctors at Chiang Mai's Maharat Hospital have concluded the suspect was suffering only from stress-related psychosomatic disorders, but the family is seeking a second opinion from specialists in Bangkok.
“I fear that because his family is wealthy and that he attended CMU [Chiang Mai University], he will not receive punishment and he will escape proper justice,” Mr Brown said.
“I have been told that he has attended a mental institution for a short time and he became a monk for a short time also. This is of course to make him look good for the judge.”
Mr Brown is now living off money raised from a fundraising page his friend helped set up on GoFundMe.com, but he says that money is running out and his long-term future is unclear.
Mr Brown said he wants his shooter to take responsibility for the actions which so dramatically changed the course of his life.
“I would tell him that because of his weakness, he took my normal life from me and caused me pain and suffering for the rest of it,” he said.
“I would tell him that he needs to make sure that I can live as best I can in my circumstances, that this is his responsibility now, and actually I feel sorry for him and his weakness.
“He could not be strong enough to act like a human towards others, the girls [at the bar], and now he has ruined someone's life.”
The victim's girlfriend, Sirikarn Phreenake, who has been caring for him since the shooting, still clings on to hope that technology may one day be able to restore Mr Brown's ability to walk.
“I dream that we will travel together. If he cannot walk, I will be the one who pushes his wheelchair wherever we go,” she said.