President Donald Trump has hit back at the criticism reportedly leveled at him by former first lady Barbara Bush, who died at age 92 a year ago.

Author Susan Page detailed in her new book, titled The Matriarch: Barbara Bush and the Making of an American Dynasty, that Bush believed Trump was the “real symbol of greed in the 80s” and was to blame for her hospitalization. Bush had a bedroom clock that counted down the seconds until the end of Trump’s presidency, Page wrote.

Trump told The Washington Times in an interview published Thursday that he had “heard” Bush “was nasty to me.”

“She should be,” he added, because “look what I did to her sons.”

“Look, she’s the mother of somebody that I competed against. Most people thought he [Jeb Bush] was going to win and he was quickly out,” Trump explained.

Trump’s response drew ire on Twitter, where critics likened his comments to his attacks on late Sen. John McCain (R-Ariz.).