If the mail arrives, the doorbell rings, or you bang a metal spoon on Zero's dog bowl, the long-haired German shepherd won't raise his head. He's deaf.

But the 8-year-old shelter dog knows when his owner, Marik Tucker, doesn't feel well. When the boy began crying in his room recently, "Zero started rolling all over Marik, shoving him with his nose," Marik's mother, Kelli Tucker, said.

Tucker got the dog for her 10-year-old son because he has cancer and a prosthetic leg, and she wanted to encourage him to walk. That Zero was deaf only strengthened their bond; Marik struggles with hearing and wears a hearing aid.

"It was like love at first sight for both of them," Oxford Animal Control Officer Sandy Merry said. "We could all see it."

There's only one problem.

It turns out Zero also is sick.

The dog was confiscated on Feb. 26 as part of a hoarding case in Oxford in which a woman was charged with 41 counts of animal cruelty. She goes to court Friday in Derby, Merry said.

The German shepherd was one among the dogs, horses, a cat, a donkey, pig, goat and chickens that were seized. Merry found him tied to a short chain at the back of the house, possibly where he'd spent all his life.

"He looked depressed," she recalled. The dog didn't wag his tail, but Merry wasn't afraid he'd bite her. He showed no aggression whatsoever, she said.

Merry's office took the dogs and cat to a veterinarian, while the state took the farm animals. The vet found the German shepherd was underweight, had parasites and a severe ear infection that could have caused his deafness, but otherwise he was all right.

Tucker had been looking for a dog for Marik for about four months. She saw the German shepherd's picture on the "Helping Connecticut Canines" Facebook page, which helps shelter animals find homes.

She brought Marik to visit the dog and they connected right away. Tucker recalled asking whether the dog was all right. Merry believed he was.

Marik named him "Zero the Hero" and they brought the him to the Tuckers' new home in Ledyard a few days later.

The shepherd seemed to need and want their company, Tucker said. He followed them constantly, tried to sit on them and stayed in the same room as the family. If he wanted something, like a rawhide chew, he'd let them know by walking in circles.

"He's just like a big love. He's kind of like Eeyore," she said. "He's just like this big thing that just mopes around, climbs onto (you) and just wants to be next to you."

The Tuckers also learned Zero is clever enough to open a toilet bowl, won't eat hamburger buns but will eat the meat, and he can reach the kitchen sink if his water bowl didn't meet his expectations.

So far, he's done only one bad thing. He ate part of the basement carpet. But Tucker said he had been in his crate at the time and got out, and he hates being alone.

She said she began noticing right away that something was wrong, but she thought it might be the crate. The dog would cough and vomit at night. Tucker thought it was because he was upset about being alone, but she took him to a vet anyway.

Zero tested positive for heartworm disease and Lyme disease. The vet said he was not well. The Tuckers already face medical treatment for their son, and yet Marik had bonded with the dog. So Tucker contacted Judi Falbo, who runs Helping Connecticut Canines, and Falbo called Chris Lamb, the president of Connecticut Animal House, a nonprofit organization that helps shelter dogs with medical, emotional and behavioral problems.

"When I heard the story, it broke my heart," Lamb said.

Lamb picked up Zero and took him to Warwick Animal Hospital in Rhode Island. A cardiologist, Mark Stamoulis, took a closer look with an echocardiogram and ultrasound. Lamb said the cardiologist felt so bad he didn't charge for the tests.

The news was bad. Zero has congestive heart failure.

Lamb said there's not a lot the vet can do, but he's doing as much as he can. Zero is on medication to treat the Lyme disease and reduce the fluid around his heart, and so far he has responded.

Lamb picks up Zero and brings him back after vet appointments. Connecticut Animal House has set up a fund and PayPal account on its website, ctanimalhouse.org, so people can donate toward the vet bills. The town of Oxford donated $200.

Tucker said Marik understands that Zero is sick, and that the dog goes to the vet like he goes to the doctor. Marik finished his last scheduled chemotherapy treatment on May 28 and returned home from Yale-New Haven Hospital on June 1.

She said Zero has been able to give Marik love and comfort despite being sick.

"Zero, he gets it," she said. "I think animals know, too. They're so sensitive to people when they're ill or having emotional turmoil that they just know."

Marik babies the dog and has a 'bucket list' for him. One of the items on the list is getting him an ice cream cone.

"Zero is a great dog, and if all of these things had been known ahead of time, he would have died in a kennel or been euthanized," Tucker said. "He never would have been adopted. I think it happened the way it did for a reason, and we'll take care of him."

d.straszheim@theday.com