The case has also raised questions about how the criminal justice system handles defendants with serious mental health concerns.
Holding a photo of his cousin outside a northwest Harris County hospital on Friday, Hieu Huynh described Nhan Le as "a good kid" and struggled to put his emotions into words.
PREVIOUS REPORT: Victim brain dead, another critically hurt after suspect attacked them with metal pipe, docs allege
"I don't know this kind of feeling. Bad, bad, bad," Huynh said.
Le, whom Huynh considers a brother, is described as brain dead in court records following a brutal attack last week.
Surveillance video obtained by ABC13 appears to show the suspect, identified by HCSO as Joshua McDaniel, knocking Le to the ground before repeatedly stomping and striking him. The attack appears unprovoked.
Investigators say the 28-year-old McDaniel attacked four people in separate incidents along SH 249 over a 24-hour period. According to court records, one victim was attacked with a machete and another with a metal pipe. Two victims, including Le, remain on life support.
"I couldn't believe it. It's too much," Huynh said.
ABC13 previously reported that McDaniel was referred to mental health treatment in February at the Judge Ed Emmett Mental Health Diversion Center when a previous assault charge against him was dismissed. In that case, he was accused of punching a man. Records show McDaniel has multiple violent convictions.
"One question. The court system. Why did it happen?" Huynh said.
Le's family, joined by Texas Crime Victims United, is now calling for answers.
"What happened? What treatment did he get? Obviously, it did not work," said April Aguirre, a crime victims' advocate.
According to the Harris County District Attorney's Office, the previous assault case was dismissed after a material witness stopped responding, leaving prosecutors to believe they could no longer prove the case beyond a reasonable doubt.
A source familiar with the case told ABC13 that, despite what court records suggest, McDaniel's mental health treatment was not court-ordered, that it was just a referral, meaning he was not required to participate.
Five months later, McDaniel is in jail and Huynh said he hopes by speaking publicly, he will raise help prevent another family from experiencing the same tragedy.
"Everyone is important, and I want to say that if they committed a crime they have to pay," he said.
SEE ORIGINAL REPORT: Man involved in 2 separate attacks that critically injured victims in NW Harris County, HCSO says