Russell Lohr, who the station reported is a regular at the franchise eatery, noticed that someone was parked in the reserved handicapped spots.
Lohr approached the unidentified man, and that's when the man reportedly hauled off and sucker punched Lohr right in the mouth.
The station reported that an 18-year-old restaurant employee intervened and began performing life-saving actions on Lohr.
Lorh ended up in the hospital with fractured skull and "significant brain bleeding," according to KOCO.
"He's incoherent. He doesn't know what's going on," the employee reportedly told police when they arrived on the scene.
Lohr remains in critical condition.
"He has a fractured skull and a broken jaw," his son, Adam Lohr, told the station. "He's having an operation [on Wednesday]."
The station reported that they are seeking a man driving a dark-colored sedan in connection with the attack.
"Makes me very angry," Lohr's son said. "He's my life. Can't lose him."
You can watch a video report on the incident here.