Fred Trump III calls uncle Donald Trump 'atomic crazy,' says he used racial slur decades ago

Fred Trump III, the nephew of former President Donald Trump, said his uncle is "atomic crazy," that he witnessed him using racial slurs decades ago -- and that he plans to vote for Kamala Harris.

The Trump way was to be "complex and sometimes cruel," Fred Trump said in an interview with ABC News' Aaron Katersky.

"And within every family -- people know this -- families are complicated. Every family has their crazy uncle. My Uncle Donald is atomic crazy. And … he has put his mark on the family history," he said, as he promoted his new book, "All in the Family: The Trumps and How We Got This Way."

Pressed to explain further, Fred Trump said it "means he does things that, even as much as I know him when he's out there now, I sort of shudder and say, 'Is this the same guy I knew? What's making him change? … What got him this way?' But that all being said, I've always had a good relationship."

He added, "But he's done really horrific things to me, which some people will say, 'How could you still want to have a relationship with him?' He's my uncle. He's family, and that means a lot."

Fred Trump, the son of the former president's late older brother Fred Trump Jr., who died in 1981 at 42, says he wrote the book in part to advocate for people with severe developmental disabilities, like his adult son William. He says this latest Trump family tell-all is not a political hit job, but rather the "full-on truth" about his uncle, who is the Republican nominee for president.

In a statement to ABC News, Trump Campaign Communications Director Steven Cheung denied the claims about the former president.

"This is completely fabricated and total fake news of the highest order," he said. "It is appalling a lie so blatantly disgusting can be printed in media. Anyone who knows President Trump knows he would never use such language, and false stories like this have been thoroughly debunked."

The younger Trump's new book includes a chapter titled, "The Race Card." In that chapter, he details his uncle using a racial slur, he said.

"I was about 10 years old, and I was at my grandparents' house, like I was a lot," Fred Trump said. "And Donald -- I could hear him screaming. And I went down to the driveway of my grandparents' house, and there was his white El Dorado convertible with two slashes. Still remember it. And he had electrical tape, because the roof was black. And he used the word -- the N-word -- twice just saying who he thought probably had done this."

The former president has consistently denied using the racial slur. Fred Trump said that despite being young when the incident occurred, he "absolutely" remembered the moment as it happened.

"OK. He did twice that day," Fred Trump said when ABC News brought up Donald Trump's repeated denials.

Fred Trump wrote in his book that some people have labeled the former president as racist, and some say he is not. But what does he believe?

"He, at time[s], espouses things that people who I believe are racist espouses. That's the best I can answer that question," he said.

"I don't believe he's a racist," Fred Trump added when pressed on the question. "I just think that he uses people, whether they're Black or they're -- whoever can help him he will use them. And, you know, call it racist or not, I don't believe in that. He uses them as props. And when he gets what he needs out of them -- votes -- he'll cast them aside."

After his uncle was elected president in 2016, Fred Trump saw an opportunity to advocate for the disabled, he said.

"I was in the Oval Office 12 times about. And that was our mission: to advocate for people with complex disabilities," he said.

He added, "It culminated in May of 2020 in the Oval Office. Donald was there, and he was very gracious. Several other folks were there, including the group that we brought down. We dispersed. I was asked to go back and see Donald. He greeted me with his familiar, 'Hey, pal. How's it going?'"

He says he "sat down for a bit" with his uncle.

"And he just came out with, 'These people, all the expenses. They should just die,'" Fred Trump recalled. "He's talking about human beings who have complex issues, and the first thing he could say was they should just die."

Fred Trump said the comment wasn't an isolated incident. He described a phone call to alert his uncle that the medical fund set up by the family for his son William was running low, a fund he says his uncle consistently replenished.

"A couple of years ago … I called him. I said, 'Donald, the fund's running out.' And without hesitation, he said, 'Your son doesn't recognize you. Let him die and move to Florida,'" Fred Trump said.

Asked if he was surprised by the comment, Fred Trump said he was. He said he told his uncle that his son did recognize him.

"Was I surprised? I don't think you could hear something like that and not be surprised," Fred Trump said. "But that is what he has become. It's sad."

"You describe your uncle as incredibly cruel. Why would you want a relationship with him?" ABC News asked.

"I'm not gonna change him I don't think there's anybody that could change him," Fred Trump said. "But I've always enjoyed time with him. And I would hope if he's not elected that he'll calm down. I don't know if that's possible. But my guess is I may not be welcome to any of the golf courses anymore. I'll find others. But I do thank him for the entree to those courses. I'm a heck of a golfer."

Fred Trump said he planned to vote for Harris, but would attend the inauguration if his uncle wins and if he’s invited.