The grief-stricken family of the construction worker fatally mowed down during a road-rage scuffle in Manhattan said Thursday they’re in disbelief — telling The Post the calm, beloved dad couldn’t have been capable of such a violent confrontation.

“It’s a nightmare,” Alex Garcia, 54, said of her husband of 28 years, Robert Velez Alvarez, who was killed Wednesday afternoon in a violent clash with another driver on the Upper East Side.

“My husband was sweet, so kind. He liked to care about other people. My husband is not going to hurt people,” she said. “This does not make any sense.”

Police said Velez Alvarez, 54, and another driver, Andre Mosby, 26, got into a feud after Mosby tapped the back of Velez Alvarez’s 2020 Chevrolet Silverado pickup truck with his 2014 Volkswagen Jetta at East 60th Street, near Park Avenue.

As the dispute heated up, Velez Alvarez got out of his truck and slashed Mosby’s tires, according to police. Mosby then allegedly slammed the accelerator on his Jetta and plowed into the older man.

But Velez Alvarez’s wife said she can’t imagine that her husband would have slashed the other man’s tires.

“He eats oranges or apples in the car when he gets hungry. He peels the orange and cuts the apple with the small pocket knife. That’s the only knife I know,” she said from the family’s home in Franklin Square, Nassau County.

“I can’t see this,” Garcia said. “When they tell me I say, ‘That’s not my husband! That’s not the man I’ve been married to for 28 years. Ask his friends, his family, his boss, his neighbors. Everyone will tell you the same.”

Velez Alvarez, a construction supervisor originally from Colombia was rushed to Cornell Medical Center, where he was pronounced dead. 

Mosby — who had three kids in the car along with his girlfriend — was charged with manslaughter. Police sources said he is claiming he was only defending himself against the knife-wielding man.

Garcia scoffed at the claim that Mosby was acting in self-defense when he allegedly rammed her husband with his car.

“He is defending himself? No…,” she said, adding she didn’t believe her late husband would have slashed Mosby’s tires if he saw that there were children in the car. 

“I don’t know about [the claim that he] cut the tire. But if he sees the kids, no. I never saw my husband like this, no,” Garcia said. 

“For me, justice is to have my husband back,” she said. “Robert worked so hard to make sure his son could have it better, leaving [at] 3, 4 in the morning, coming home [at] 7, 8 at night. Sometimes working 24 hours.

“He wanted to see his son get [to] the graduation.”

The victim’s son said even his dad’s boss thought he was joking when he relayed the police account.

“I never saw him yell,” Steven Velez Garcia, 25, told The Post. “I worked with him. My uncle worked with him. He never yelled. The harshest thing I ever said when I worked with him, I heard him say, ‘This is not something to do.

“Right after it happened I called his boss and he didn’t believe me,” he said. “He just started yelling, ‘No, tell me you’re joking, tell me this is a joke!’ My dad was like family to him. He didn’t believe it.

“He didn’t believe my father could be involved in that. He’s just not the type of man. I’m still in shock. It doesn’t feel real to me.”

Police said Mosby has two prior arrests, including a 2017 Bronx bust during which he and an accomplice were charged with punching the victim and stealing $400. He also has a subway fare evasion charge from 2016. His arraignment in Manhattan Criminal Court was pending Thursday.