About a year ago, Costas Triantafilos was halfway home after leaving his Dundalk restaurant, Costas Inn, before he realized he forgot to say goodbye to a customer at the bar.

He turned his car around. He couldn’t bear the thought of a patron not feeling acknowledged.

“Who does that? It’s just the person that he was,” his son Pete Triantafilos said. “He taught me everything I know.”

Costas Triantafilos, who emigrated from Greece in 1955 and ran the popular seafood eatery with his family for decades, died Monday from apparent carbon monoxide poisoning, Pete Triantafilos said. He was 85.

A car was left running in an attached garage, which caused carbon monoxide to build up in the home in the 11200 block of Old Carriage Road in Glen Arm, investigators told WJZ. Pete said his father inadvertently failed to turn the car off when he didn’t press the ignition button hard enough Sunday night.

“It was just a freak accident,” Pete said. “That’s what’s painful for everyone.”

His wife of 64 years, Mary Triantafilos, was in the house and also taken to the hospital. Her son said she’s doing “very well” physically and was discharged Wednesday night.

”She has a broken heart,” Pete said.

Mary is far from alone. Since news of Costas’ death shocked Dundalk and the greater Baltimore area, friends, family and customers have shared memories and grieved, both online and at the restaurant at 4100 North Point Blvd.

George Kazakos, co-owner of Pizza Roma in Edgemere, a five-minute drive from Costas Inn, called Costas his best friend. They met in the 1980s, and Costas and Mary became godparents to his daughter. If they missed their regular coffee together in the morning, Kazakos and Costas made sure to call each other each day.

“‘What, you didn’t have a quarter to call me?’ That was his line if we didn’t talk,” Kazakos said.

Kazakos said the community lost much more than a successful businessman.

“You couldn’t meet a finer man,“ he said. “I’ve never seen him dislike a person. If he liked you and really liked you, it was like he was all in. You knew he was your friend.”

Pete, who described the response as “overwhelming,” said he couldn’t close Costas Inn on Monday “because he wouldn’t want me to.”

“People came pouring in on Monday just to pay their respects and mourn, and to honor him and to sit and have a drink and give the staff a hug,” he said.

Over the years, Costas Inn has earned a reputation for its crabs, crab cakes and pit beef, along with its house-blended seasoning, which was featured on NBC’s “Today.” But beyond the food, the restaurant is known for its camaraderie and sense of community among regulars, Pete said, whether they gathered for a Ravens game or a family meal.

On Sunday, Costas was there as he was every day, cheering on the University of Maryland as they advanced to the Sweet 16.

“We were all watching it together, and he’s like, ‘They’re gonna win but they’re not gonna cover,‘” Pete said with a laugh.

Mourners have emphasized Costas’ generosity, whether it was helping with a medical bill, providing a free meal or simply offering a comforting shoulder in times of need. ”He would do anything for anyone. He was just good-hearted,” Pete said. When the Small Business Administration offered loans to businesses affected by the Key Bridge collapse, Costas Inn passed.

“We make our ends meet but a lot of places, they’re hurting more than we are,” Costas told WYPR recently.

Costas, a graduate of Sparrows Point High School in 1959, “built the American dream,” Pete said. More importantly, he did it for his family: Pete is the chief operating officer of Costas Inn, while his brother, Nick Triantafilos, is the director of communications and strategic planning. Many other family members, like the brothers’ sister, Christine Lambros-Shifflett, have also worked for the restaurant.

Now, the tight-knit family must figure out how to move forward. That includes a second location for their restaurant in Timonium, where Costas developed his love of horse racing as a thoroughbred owner. The family eyed a possible April opening, but Pete said it “might be a little delayed” now.

“We’re going to continue with his dream and the legacy that he’s created,” Pete said. “I just wanted him to see the whole thing when it was completed. … He’s not going to be there to share in it, but hopefully he’ll see it.”

For now, it’s a time to grieve and celebrate Costas’ life. The family will host two public viewings — the first at Connelly Funeral Home in Dundalk on Sunday from 1 p.m. to 8 p.m., followed by a second viewing at St. Nicholas Greek Orthodox Church in Greektown from 10 a.m. to 11 a.m. on Monday before the funeral service. The restaurant will be closed Monday, Pete said, to allow staff to attend.

“We’re just trying to work through it together,” he added, “and all the outpouring of support from the community has been a big help.”

The Banner publishes news stories about people who have recently died in Maryland. If your loved one has passed and you would like to inquire about an obituary, please contact obituary@thebaltimorebanner.com. If you are interested in placing a paid death notice, please contact groupsales@thebaltimorebanner.com or visit this website.