They say a dog is a man’s best friend – but for five-year-old Koen, Valak was much more.

The five-month-old American staffy was Koen’s companion, guide, confidant and best pal. Valak would watch over Koen as he slept and keep him company while he played outside.

But on Thursday, November 24, Valak went missing.

Koen’s mum Kirsty Gray says her son, who has autism and attention deficit hyperactivity disorder, is devastated and struggling to cope without Valak.

“They’re best friends,” Ms Gray says. “Valak was more of a companion to Koen and was able to calm him down.

“Koen has sensory issues so when he’s having a sensory overload, Valak’s usually right there with him. He was sort of like a service dog for Koen.”

The family was on holiday at the time Valak went missing. A friend would come past Ms Gray’s Kurunjang home twice a day to feed and check up on Valak and his mum.

But Valak escaped. He was last seen at Kurunjang primary, where Koen goes to school.

“We used to walk Valak to school,” Ms Gray said. “So he was probably afraid when we weren’t home and went to the one place he knows to go to look for Koen.”

The family has been desperately searching for their missing pup, who is an orange/tan colour with markings on his chest.

They’ve put up flyers around town, posted on Facebook sites and have placed Gumtree advertisements.

Ms Gray is urging anyone with information to contact her on 0403 514 046.

“We just want him home, no questions asked,” she said.