This 86-year-old tech wiz nicknamed ‘Mr. iPhone’ started teaching computer classes for his senior living community and transformed the way people engaged with their families

Andy Petro, 86, gets stopped by his neighbors half a dozen times a day in his senior living community in Roseville, California. One neighbor can’t get their texts to go through. Another can't toggle with their brightness, and one woman wants to learn how to send her grandchild happy birthday balloons through the screen.

“It was like I opened a candy store, and all the candy was free,” says Petro, who modestly admits to solving 90% of the Apple-related troubles he encounters.

Most recently, a woman stopped Petro while sitting at dinner because she couldn't get any calls to come through. Petro was at her door in an hour. “That just saves them from having to ride down to the Apple Store,” Petro tells Fortune. "Now she can make phone calls. That's nice."

While he’s known to his family as Andy, he’s savvy Mr. Apple to his fellow seniors in Sonrisa Senior Living.

In addition to tapping him on the shoulder for last-minute assistance, people block off time to hear Petro’s tech talks. As president of the senior center’s Apple Club, an organization for people who want to make the most of their iPhone's features, Petro hosts a monthly hour-long class in the community theater with 20 to 25 neighbors between ages 75 and 95. He answers questions, explains new features or updates, and gives tips on the best ways to communicate (he's sure to have the latest versions himself). As a longtime tech pro and teacher, he loves giving back and helping people feel confident about new forms of communicating as they age.

“Since my brain still works, I brought all my knowledge and became Mr. iPhone guy,” he says.

After Petro joined the Marine Corps in the late 1950s, he was encouraged to study electronics before transferring to a base in Japan. After returning from his service, he secured a job in aeronautics in Southern California. For the next several decades, between jobs and startups, he also taught classes in technology and business systems. When the first Apple device came out in the 1970s, he was among the most eager customers.

“I fell in love with Apple products when the first one came out,” he says, having bought the Apple II Plus computer system. He immediately saw its impact on his son, who had been struggling with dyslexia and wasn’t doing well in school.

“A miracle happened,” he says. “He could now type, and when he was typing, he didn't have the same dyslexic problems as he does when he's writing with a pencil in his hand.”

While novel technologies impacted his family, they also encouraged him to keep learning and teaching others throughout his career. Thus, teaching at his senior living center wasn’t far from his old stomping grounds.

After retiring at age 70, Petro and his wife moved to an independent house in a senior community near their family. There, he was introduced to his first Apple club and joined the board of directors for 15 years. As he aged and moved to a senior living facility, he started his own tech club for the residents.

While some of what he teaches is relatively beginner, he puts his ego aside and helps his neighbors find the Apple store or their phone’s carrier location when the problem is out of his wheelhouse.

“When people come to my classes, they're really very enthusiastic about learning something new, and then feel good about it and feel good about themselves,” he says, such as taking photos and texting them to family. “It's really something that will allow them to communicate a little bit better with their grandchildren and their children.”

Petro emphasizes that people underestimate older adults and assume they don’t want to learn the latest updates. However, he says, many are eager to find ways to streamline communication and use new features, especially for those who may have Parkinson’s and need to learn how to use voice recognition to limit typing on the screen, for example. “In every new version that comes out, there's really a number of things in it that are good for somebody who's 85 or 90 years old,” Petro says.

It doesn't hurt that Petro gets to interact with countless new faces as he's likely to be stopped dozens of times before the next official class.

“When I got here, I said, ‘anybody who's interested in Apple, come and see me,’” he says.

If you have personal stories on seniors 80+ who are sharing their life lessons, finding new hobbies, skills, and empowering aging adults, please reach out to alexa.mikhail@fortune.com

This story was originally featured on Fortune.com