Annabelle Weiss, 92, enlisted in the U.S. Marines when she was 20 years old. She served two years, working as a driver and inspecting plane engines, before she was discharged in 1946.

Later Weiss, who lives in Lindenhurst, New York, worked as a nurse. She was eventually diagnosed with thyroid cancer and experienced various health problems related to her service. In 2013, she learned about America's VetDogs, an organization that pairs veterans in need with trained service animals. That's how she got Joe, her yellow Labrador, and now the pair are inseparable.

TODAY spent a day with Weiss and Joe to learn more about their relationship, and see how he helps her get around.

Click below to view the slideshow.

At home: 1:15 p.m.

Weiss, who lives alone with Joe in a Long Island suburb, spends the mornings at home and usually goes out in the afternoons. When they leave, Joe knows it's time to work.

"In the house, he's a dog," Weiss said. "When he's outside, he has his vest on, and he's on the job like a cop."

"I think he's pretty intelligent," she added.

They're also about the same size. Weiss said Joe weighs about 85 pounds, while she weighs about 90 pounds.

"I'm not even five feet anymore," she said. "I've shrunk, of course!"

Joe helps Weiss open a dresser drawer in her bedroom. Michael Rubenstein / for TODAY

Joe is trained to bring Weiss items she drops, open and close doors, and brace her when she needs to get out of a chair or walk up or down stairs.

"I have rags on my dresser drawers and I tell him 'tug,' and he opens them," she said. "I tell him 'push,' and he closes them."

"He can get my phone," Weiss continued. "I tell him 'phone' and he brings me the phone. Not that I always need it. Sometimes I say it just to keep him sharp."

Going for a drive: 2:15 p.m.

Joe rides in the backseat while Weiss drives. Michael Rubenstein / for TODAY

"Yes, I still do drive!" Weiss said. "People say, boy, you're such a peanut, what are you driving for? If only they know what I used to drive! (In the Marines) I drove jeeps, big trucks, station wagons. I used to drive the colonel around."

"Joe has the whole back," she continued. "I fold the seats down for him. He just sleeps. He doesn't even stick his head out the window. He was trained beautifully."

Joe leaves golden hair everywhere, but Weiss, who has had pets all her life, doesn't mind.

"I vacuum him on the low setting," she said. "He loves it."

At the library: 2:33 p.m.

Weiss and Joe at the library. Joe often puts his paws on the desk while she's checking out her books. "He says hi to everybody," she said. Michael Rubenstein / for TODAY

"Do you think that looks like a good book, Joe?" Weiss asked during a trip to the Lindenhurst Memorial Library, where her name is printed on a shiny blue star in a display honoring veterans.

Weiss is part of a reading club there, and called Joe the unofficial mascot.

At the diner: 3:13 p.m.

At the diner, Joe stays close. He checks for crumbs before taking a nap at Weiss's feet. "He'll follow me to the end of the earth," she said. Michael Rubenstein / for TODAY

"This is where I hang out a lot," Weiss said of the Lindenhurst Diner. "They're going to charge me rent one of these days! Everyone knows Joe. He goes right under the table. He looks for crumbs, and then he goes to sleep."

"We go to the diner once or twice a week," she continued. "I'm not much of a cook. The first time I brought Joe in, there was a young man cleaning the tables — he doesn't speak English; he speaks Spanish — and he saw me with the dog, and he said, 'Oh, perro.' I corrected him and said 'hijo!' I speak a little Spanish. I told him, 'He's not my dog, he's the son I never had.'"

Joe greet the diner's owner. "If he stands up on his hind legs, we're almost the same height," Weiss said. Michael Rubenstein / for TODAY

On their way out, Joe often jumps onto the host stand to say goodbye to the owner.

"At first, they would say, 'Oh Joe! Oh Joe!' and I finally said, 'Who's paying the bill here?'" Weiss joked. "Now they say, 'Hello, Annabelle.'"

At the park: 4:32 p.m.

Weiss and Joe take a walk through the park. Michael Rubenstein / for TODAY

Back at home, Weiss takes Joe to a nearby park.

"We come here almost every day," Weiss said. "Joe loves it here. He loves the birds, but they don't love him."

"He changed my life, he really did," she added. "Without him I would be at the house a lot. Now people call me and I'm never home!"

Corrections & Amplifications: An earlier version of this story described Joe as a golden retriever. He is a yellow Labrador.