Last week, officials at San Francisco General Hospital said Stow was showing significant improvement after undergoing a third round of surgery on Aug. 10.
But his family said on Monday that Stow has been running a high fever and tests showed that he had developed urinary tract and staph infections.
The family's statement said that Stow was being treated with antibiotics and doctors are using an ice vest to cool him down, but that his body temperature remains high. He remains conscious and able to recognize family members, however.
In their statement, Stow's family also addressed violence during a game between the San Francisco 49ers and the Oakland Raiders at Candlestick Park Saturday, when two men were shot and another was brutally beaten in a stadium restroom, and numerous fights broke out throughout the stadium.
Stow's family said they were dismayed that his condition had not served as a warning against violence, particularly at sporting events.
"We have felt, since March 31st, that this tragedy did not happen to Bryan for nothing. We had hoped it would teach people that violence, specifically at sporting events, is unnecessary and wrong. Nobody should feel afraid to root for their team, or bring their families to games," said Stow's family.
Stow was attacked outside of Dodger Stadium in Los Angeles after the March 31 season opener against the San Francisco Giants. He was walking from the game with three friends when two men wearing Dodgers clothing approached him from behind, according to Los Angeles police.
The two suspects first taunted Stow, who was wearing Giants paraphernalia, and then hit him from behind, which caused him to fall to the ground. They kicked Stow while he was on the ground before fleeing in a car, and Stow was rushed to a local hospital.
Swelling in Stow's brain prompted Los Angeles doctors to remove a portion of his skull to relieve pressure on his brain. Doctors from San Francisco General Hospital said the procedure saved Stow's life, but that replacing the missing skull fragment has remained challenging.
Doctors attempted to replace the skull fragment in mid-July, but that caused complications when fluid collected and was trapped underneath the fragment, and doctors were forced to operate within an hour of replacing the bone fragment.
After doctors again replaced the skull fragment with a custom prosthetic bone flap on Aug. 10, they said that Stow was tolerating the procedure well and were hopeful he would continue recovering. While the bone flap remains in place, Stow's infections are preventing further necessary procedures, according to his family.
Before his injury, the 42-year-old Santa Cruz father of two worked as a paramedic in Santa Clara County.
On Aug. 10, two men charged with Stow's beating pleaded not guilty in Los Angeles County Superior Court.
Louie Sanchez, 29, and Marvin Norwood, 30, each pleaded not guilty to one count of mayhem and assault in connection with the attack on Stow, according to Los Angeles County District Attorney's Office spokeswoman Jane Robison.
The two men were arrested in late July after police examined hundreds of clues and interviewed hundreds of witnesses. The arrest of Sanchez and Norwood came as a surprise because police had already arrested a different suspect, Giovanni Ramirez, but exonerated him shortly after arresting Sanchez and Norwood.
Sanchez and Norwood are next scheduled to appear in court Sept. 30 at 8:30 a.m. for a preliminary hearing.