Waldrop says a violent car wreck, which happened 20 years ago in Alabama, left McCann in a coma for months.
He suffered brain damage, which took away his ability to play sports and live a normal life.
So when Waldrop heard that McCann was shot by a Shawnee Police officer Monday morning... "I just believe it was a suicide by police," he said. "He wanted somebody to kill him and he saw his chance."
The Oklahoma State Bureau of Investigation says just before 1:30 a.m. Monday, McCann was trying to force his way into a neighbor's apartment.
When police arrived, he allegedly came to the door with a knife in his hand.
"He was told to put down the knife several times," says OSBI Spokesperson Jessica Brown. "He refused to do that and actually began running toward these officers."
Brown says an officer shot McCann twice in the torso, killing him at the scene.
A neighbor, Coeta Little, said McCann showed violent tendencies while living at the apartment.
"He went from evil to angel, to be honest," she says. "I mean, he was nice and then all of a sudden he would flip out."
Kristal Combs, McCann's ex-wife, says he had mental problems and spent time in psychiatric hospitals; she claims state services did not do enough to help him.
"He might have had his faults, but he did love his son," Combs says, "and now I'm stuck, left picking up the pieces."
McCann's family says medication would help curb seizures and violent outbreaks, but he wouldn't regularly take the medication.
The Shawnee officer who shot McCann is on administrative leave, pending the OSBI's investigation.
Brown says the District Attorney will eventually decide if the shooting was justified.