Former Illinois coach Ron Zook said Brent, a third-year player who made the first start of his career in the opener against the New York Giants, was trying to help Brown make it in the NFL. Brown joined the Cowboys in October after he was released by the Indianapolis Colts.
"It was Jerry's dream, and Josh was trying to help him any way he could," Zook said.
Zook said he spoke with Schaffer, who said he had made contact with Brent.
"He said Josh was distraught, and he didn't care about himself or what was happening to him," Zook said. "All he cared about was Jerry's family."
Brent was arrested in February 2009 near the Illinois campus for driving under the influence, driving on a suspended license and speeding, according to Champaign County, Ill., court records.
In June 2009, Brent pleaded guilty to DUI and was sentenced to 60 days in jail, two years of probation, 200 hours of community service and a fine of about $2,000. As part of his plea deal, prosecutors dropped one count of aggravated DUI/no valid driver's license. Brent successfully completed his probation in July 2011, court records show.
Brent, a nose guard, has played in all 12 games this season and played a bigger role than expected with starter Jay Ratliff battling injuries. He has 35 tackles and 1 1/2 sacks and might have started Sunday against the Bengals because Ratliff is out with a groin injury.
The Cowboys signed Brown to their practice squad Oct. 24, but he hasn't been on the active roster. He was released from the Colts' practice squad Oct. 20. Brown played in one game for the Colts, a loss to the New York Jets on Oct. 14.
"On behalf of the entire Colts family, our sincerest condolences go out to Jerry's family and friends," Colts general manager Ryan Grigson said in a statement. "He was a good teammate that was well liked by all. Today's tragic news is just another reminder of how fragile life is and how everyday given is a gift."
Brent and Brown played at Illinois from 2007 to 2009. Brent played as a freshman and finished his career with 71 tackles and five sacks. Shortly after his guilty plea on the DUI charge, Brent entered the supplemental draft with a year of eligibility remaining, and the Cowboys took him in the seventh round.
Brown, who took a redshirt season at Illinois the year before Brent arrived, had 13 tackles combined in 2007 and 2008 but didn't play in 2009.
"I can't believe it," Travon Bellamy, a former Illinois teammate, wrote on Twitter. "Before people pass judgment on Josh, they need to know that he is a good person that made a bad mistake."
Brown played for San Antonio in the Arena Football League this year. In 2011, he played for Jacksonville in the AFL and the Hamilton Tiger-Cats in the Canadian Football League.
He was born and grew up in St. Louis, attending Vashon High School.
Associated Press writers Michael Graczyk in Houston and Sara Burnett in Chicago contributed to this report.