Curtis Ingraham uses Twitter to vent his political frustrations—like many left-leaning users in the Trump era.

To an audience of just a few hundred followers, the Northern California-based teacher expresses outrage at new White House policies, engages with popular #resistance figures like former George W. Bush speechwriter David Frum and the Krassenstein brothers, and bashes Trump’s right-wing media cheerleaders on Fox News.

While most of his tweets go largely unnoticed, a few people have taken notice because of what he has to say about one media personality in particular: his sister, Fox News primetime host Laura Ingraham.

“I think she’s a monster,” Curtis repeatedly said in an interview with The Daily Beast.

Since Donald Trump launched his presidential bid in 2015, a number of his prominent backers have faced public hostility from family members critical of Trumpism and the Republican agenda under his watch.

Trump special counselor Kellyanne Conway’s husband, longtime Republican operative George Conway, has used his Twitter account to make his displeasure with the administration well-known, despite his wife’s position as a top flack for the president. Republican Rep. Bob Goodlatte’s son accused his father of “political grandstanding,” and donated thousands of dollars to the Democratic running for his father's congressional seat. And White House adviser Stephen Miller—an architect of Trump’s most anti-immigration policies—has earned public condemnations from his uncle, elementary school classmate, and childhood rabbi.

Since earlier this year, the elder Ingraham sibling has used his Twitter account for seemingly one purpose: criticizing Laura, whose pro-Trump, hardline stances on immigration and culture-war issues have earned her praise from the president and far-right figures.

Curtis Ingraham encouraged advertisers to boycott Laura’s show following her comments about Parkland school-shooting survivor David Hogg, and apologized to LeBron James after his sister mocked the NBA star’s criticism of Trump by saying James should “shut up and dribble.”

But Curtis has also dished out a few eyebrow-raising claims about the Ingraham kids’ upbringing and Laura’s life.

He wrote on Twitter that she once mocked a black college classmate by speaking “jive.” He shared that one of Laura’s adopted immigrant children called him a “Dummy-crat.” He pointed out that their grandparents were Polish immigrants, and said his sister was influenced by their late father’s alleged sympathy for Nazis.

“My siblings and I are shocked and saddened to learn of these false and hurtful online postings,” Ingraham said in a statement to The Daily Beast. “Although we’ve been estranged from him for many years, we love our brother and miss him very much.”

And off Twitter, Curtis doesn’t have much better to say about his sister.

In a telephone interview with The Daily Beast, the soft-spoken older brother criticized Laura’s show, described her personality as “destructive,” and characterized her as generally “extremely angry.”

“She’s very smart, she’s well spoken, but her emotional heart is just kind of dead,” he said. “And you see it in her face when you see her on TV. She’s ready to destroy. She does not listen to understand—she listens to respond. And her response is always an attack.”

The point of the Twitter account, Curtis said, is not to air out his sibling rivalry or resentments. Rather, he uses it to point out how she has disappointed her older brother.

“The reason I’m sharing these details is because of what is happening in our country,” Curtis said. “I feel like a bit of a whistle-blower in trying to unveil hypocrisy.”

He added: “Our country has been thrown into this divisive state. So now I feel like I have got to speak out, I’ve got to speak out for my own sanity.”

Curtis said he didn’t always believe his relationship with his sister would be adversarial, even though she held political views that he disagrees with. At one time, Curtis said, he and Laura were “very close,” vacationing together, spending time in Washington, D.C., and sharing personal details about their lives.

But he acknowledged that they have “very limited contact at this point,” which he attributes to political differences rooted particularly in her past statements about the LGBT community.

As a student at Dartmouth in the 1980s, Ingraham ran the school’s right-wing newspaper, The Dartmouth Review, which had been known for its controversial statements about race. She infamously assigned a reporter to attend and secretly record a gay students’ association meeting in which some closeted students shared their experiences. The paper published excerpts and quotes from the meeting, which ended up outing at least one student, and labeled gay students with offensive slurs.

In a 1997 op-ed apologizing for her actions, she attributed her changing opinions about issues including same-sex marriage to her experience witnessing her brother’s loving relationship with his longtime partner, who died of AIDS.

Curtis told The Daily Beast that, at the time, he was moved by the piece.

But he said Laura became more religious in subsequent years, and began to waver in her newly empathetic positions on LGBT rights. In private conversations with her brother about issues like same-sex marriage, she said she would have to “agree to disagree” with him.

He told The Daily Beast that, to him, Laura’s change of heart on LGBT issues and gay marriage at the time constituted a betrayal.

“That goes against my ethics,” he recalled thinking. “You’re destroying me. It’s hideous, it’s hideous behavior.” He added: “That’s what I’m trying to unveil here, the hypocrisy. ‘Family’s first, I know about gay rights, my brother is gay.’ It’s all a sham.”

Curtis said that for a long time he chose to publicly overlook their sharp political differences.

But the addition of her incendiary show to the Fox News prime-time lineup and the stark oppositional politics of the Trump era prompted him to break his silence.

“The divisiveness in this country has cut through not just friendships, but it’s cut through families,” he said. “I was doing that dance with my sister for a while, we were very tight, her anger was funny to me back then.”

Curtis said he is saddened by how his sister’s outspoken punditry has destroyed their relationship.

“It is not easy for me,” he said. “My heart has been bruised, it has been kind of irreparably bruised. But I’m trying to illuminate and shed a light on hypocrisy.”