The benefit will raise money to help Downs with medical expenses after he's suffered brain injuries due to multiple concussions from football.
"We're just trying to give back to the community," Cobb said. "Sometimes, it takes a while for him to answer the phone. His speech is slurred, so it's a hard thing to deal with."
Downs was a star safety at Rice before graduating in 1981.
He signed with the Dallas Cowboys as a free agent and played for Dallas from 1981 to 1989.
He was named All-Rookie in his first season with the Cowboys. He earned All-Pro in 1984.
Cobb believes Downs is suffering from chronic traumatic encephalopathy, a progressive brain condition that's thought to be caused by repeated blows to the head and repeated episodes of concussion.
"You can only detect CTE when you're dead, so we're trying to research it when you're alive," Cobb explains.
The idea for the benefit came when Cobb had lunch with alum Brian Patterson, and they were looking to help someone from the Rice community.
Cobb's the founder and President of Trevor Cobb's Helping Hands Foundation, a non-profit organization that conducts events for people with medical setbacks and financial hardships.
Cobb has had his share of medical challenges. He suffered from a stroke in 2013 and a heart attack in 2015. He says he's still recovering from those injuries, and he feels "fine."
The athlete holds nearly every rushing record in Rice football history. He was named the 1991 Doak Walker Award winner and recognized as the best running back in the nation. His Rice accolades include most season and career rushing attempts (306/1,091) and career rushing touchdowns (38).
Cobb is a proud graduate of J. Frank Dobie High School.
The Rice Is Down With Downs benefit is on Friday, April 22, from 6:30 p.m. to 10:30 p.m. at The Brian Peterson Performance Center at Rice University.