Teenage Wendy's employee shot in the head 'by customer who wanted barbecue sauce'

A teenage Wendy's employee was shot in the head after a customer got into a row about barbecue sauce.

Brian Durham Jr wasn't even involved in the dispute when he was blasted.

The 16-year-old was shot after a customer allegedly opened fire into the drive-thru window of the Arizona fast-food joint and then jumped into the passenger side of a car that sped off, according to police.

Police say they have arrested the alleged gunman – Theotis Polk, 27 – and charged him with aggravated assault.

Durham Jr is still alive after hours-long emergency surgery, his dad, Brian Durham Sr, told KSAZ-TV.

He told the news outlet that the bullet grazed the boy's head but luckily missed his brain at the Phoenix store.

Dad Brian Durham Sr, left, said it was a miracle his son was still alive (FACEBOOK)

"My son just stayed quiet and had the guy’s change in his hand," Durham Sr said. "[He] just stayed quiet while the other two was in confrontation.

"It was very nerve-wracking hearing that your son got shot because you don't know what. Is his leg shot? Is he dead? Lot of things is racing through your mind."

Durham Sr went on to tell KPNX his son was standing at the register between the alleged gunman and his intended target who told the suspect that he had to pay extra for the barbecue sauce.

“So, the dude on the outside tells him, ‘No, you [have] to pay for it,’ so he started getting louder,” Durham Sr said.

“The [suspect] got up, out of his car, walked up to the window and just shot, didn’t care about life.”

Durham Sr described it as a "miracle" that his sonwas still alive.

"My son ain't supposed to be standing. If he would have switched two seconds to the left, maybe one, he would have been gone," he said.

The shooting happened at a Wendy's (12 NEWS)

Now the focus shifts towards recovery, which is murky at this point.

“They said how the bullet fragments [hit his brain], they don’t know how his speech is going to be,” Durham Sr said.

“They give him commands and he moves his fingers and toes but can’t talk.”

He got the job to help his mom with bills while being a full-time student, Durham Sr said.

The family asked for support to help with medical bills and created a GoFundMe account.