The mother, who anonymously shared her story on the Love What Matters Facebook page, shared a photo that was two years old but which still moves her when she sees it.
She explained her son Lucas is “slightly on the spectrum”, and their dog Max is an abused rescue dog they saved from mistreatment.
“The abuse caused [Max] to fear human touch, except for Lucas,” she wrote on 14 February.
“They are best friends. Max is Luke’s protector.
“They have taught each other so much. About trust, about love, about companionship.”
The mum continued: “It’s amazing to watch them together.”
The post was liked more than 8,000 likes in one day and many parents commented on it to share tales of their own children’s relationships with family pets.
“Same here,” one mum wrote. “We adopted from the shelter and she is absolutely my daughter’s dog. My four-year-old is high function ASD (autism spectrum disorder) and Roo is our lifesaver.
“She keeps the night terrors away and knows exactly what to do to calm her down during a meltdown.”
Other parents also shared photos of their dogs.
“We have the same,” one mother wrote. “My stepson has ADHD. When we rescued Abbie this kid was super afraid of dogs.
“But within minutes these two became inseparable. He is her human. She cries when he leaves and he will run back into the house if he forgets to tell her goodbye. Their love is greater than anything.”
Another woman wrote: “I love this. At 30 years old my rescue taught me for the first time the truest meaning of compassion, loyalty and dedication.”
One mum also added: “My daughter is on the spectrum as well. Even if she is having an issue, her word, she can always engage with her animals.
“We call her the cat whisperer.”