Unbelievably, this isn't the first time Alfie has detected an illness before anyone else. The family noticed that Alfie would often lick the leg of their other dog, Cass.
"We took Cass to the vet in December and she was diagnosed with a tumor in her back leg, exactly where Alfie had been sniffing and licking," said Sharlene. "I think he was trying to lick away the cancer." Unfortunately, Cass has since passed away, and the loss of his dog sister has taken an emotional toll on Alfie.
But Alfie still has a great friend in the house. Young Mark and Alfie do everything together, according to Sharlene.
"They have this unbelievable bond," she said. "Alfie's instinct is incredible. He knows when something is wrong with Mark before we do, even when he's just feeling unwell."
After several months of treatment, young Mark's eyesight has stopped worsening, and he's more able to do the kinds of things other 5-year-old children enjoy, like after-school sports and walking around the block with the dog who's always looking out for him.
It's no secret that dogs can be impressively in tune with their family's needs. Check out the dog who jumped in front of a bus to save his blind owner or the dog who amazingly called 911 during a fire to save her blind owner.