Did brain damage make ex-Dallas Cowboy homeless?

COSTA MESA, CA -- Chris Brymer was a former star athlete at USC and ex-Dallas Cowboy. Today, he is homeless.

His family and ex-wife are questioning whether brain damage from football is to blame for his life spiraling out of control.

When ABC7's Curt Sandoval found Brymer sleeping under a tree in his parent's front yard, the Apple Valley High School football standout said he didn't need help.

But most of Brymer's family and friends suggested he may not know that he needs help, because they believe he suffers from chronic traumatic encephalopathy (CTE), a disease from repetitive brain trauma.

MORE: Did brain damage lead USC football star Chris Brymer to homelessness?

Many asked how someone suffering from CTE can get help, and ABC7 found the answer with Anthony Davis, another former Trojan.

The All-American running back led USC to two national championships in the 1970s. Today, he'll tell you he wished he would've pursued his baseball career instead of football.

"I was speaking to a mother the other day and I said, 'If your kid is a good baseball player,' which she said he was, 'then keep him there,'" Davis said.

Davis said after several episodes of memory loss, such as forgetting if he locked his doors, and a time when he blacked out on the 405 Freeway, he finally put his pride aside and went to the Amen Clinic in Costa Mesa to have his brain scanned.

"And then when I came back for the follow up, he goes, 'Are you ready for me to tell you about your brain?' I said, 'Yes.' He said, 'You have the brain of an 85-year-old man,'" Davis recalled.

Davis was only 55 at the time.

After a year of "brain nutrition," which included neuro feedback and hyperbaric oxygen, Davis reported drastic improvements.

"He says, 'Doc, I feel great. This is amazing. I really want you to help my friends,'" Dr. Kristen Willeumier with Amen Clinics said.

Davis' results led the Amen Clinic to a pilot study of 30 current NFL players and it quickly evolved to more than 100. Willeumier said the study produced staggering results.

"When we had the first 10 guys come in and work with us, I was shocked the number of people who were contemplating suicide," Willeumier said.

Former USC football star and NFL Hall of Famer Junior Seau committed suicide in 2012. His autopsy revealed he suffered from CTE.

MORE: Loved ones of former football star reach out to get him out of homelessness

While the national average for depression is eight to nine percent, the Amen Clinic study found 28 percent of the players tested showed severe depression.

"It's from using your head as a weapon," Willeumier said. "If you're going to hit your head, your frontal lobes, into a teammate every day, just imagine if you're a lineman."

The Amen Clinic said they would not only want to evaluate Brymer, who was a lineman, but to help him rehabilitate.

"It's all about the rehabilitation process. You bring someone like Chris Brymer in here, you know what's really important to me is to make sure he has the support so we have recommendations so that he can follow through on," Willeumier said.

Davis is proactive in speaking with former players of all ages to have their brains evaluated, and explains that if there is a damage, he wants people to understand that it can be rehabbed.

The family of Brymer said whether he will consider accepting help may depend on if he's willing to rehab his brain first.