(CBS News) – President Trump had a “spark of kindness” earlier in his life — but it was extinguished by a domineering father who made him ashamed of showing emotion, his niece said. Mary Trump is opening up about the family she calls “dysfunctional” and “dangerous” in her new memoir, “Too Much and Never Enough: How My Family Created the World’s Most Dangerous Man.”

Mary Trump is the daughter of Fred Jr., the president’s older brother who died in 1981 from a heart attack resulting from alcoholism. He was 42. She’s also a trained psychologist and the president’s only niece.

She told ABC News in an interview that aired Wednesday that her grandfather, Fred Trump, was a “sociopath” who damaged Donald and the rest of the family.

“He had no empathy,” she said of her grandfather, who headed the family real estate firm and died in 1999. “He was incredibly driven in a way that turned other people — including his children, his wife — into pawns to be used for his own ends.”

She said he “severely restricted the range of human emotion that was accessible” to his son, her uncle Donald.

“Certain feelings were not allowed,” she said, adding some examples: “Sadness. The impulse to be kind, the impulse to be generous. Those things that my grandfather found to be superfluous, unmanly.”

Mary Trump says this suppression led to Donald’s cold treatment of Fred Jr., who struggled with alcoholism. She claims that when her father was dying in a hospital, Donald went to the movies rather than spend time with him.

She said Donald may have believed it would have “looked bad” to his father to be there for Fred Jr. in the hospital, or that it would have been “too burdensome” for him to sit and wait for a phone call with updates. Fred. Jr. ultimately died without any family members around him, she said.

The president, in a rare admission of regret, told the Washington Post in 2019 that he felt bad about how he and his father had pressured Fred Jr. to run the family business when it “was just something he was never going to want.”

“I think the mistake that we made was we assumed that everybody would like it. That would be the biggest mistake,” Mr. Trump said.

White House Press Secretary Kayleigh McEnany last week dismissed Mary Trump’s memoir as “a book of falsehoods.” The book was released Tuesday by Simon & Schuster, a ViacomCBS subsidiary.

Mary Trump said she wrote the book now to warn the country about the dangers she sees in her uncle as he runs for a second term in the White House. She said she sees parallels between the chaos of her family and the chaos seen across the nation under his leadership.

“I saw firsthand what focusing on the wrong things, elevating the wrong people can do — the collateral damage that can be created by allowing somebody to live their lives without accountability,” she told ABC News anchor George Stephanopoulos. “And it is striking to see that continuing now on a much grander scale.”

Asked what she would tell him if she saw him in the Oval Office today, she replied, “Resign.”

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