Donald Trump’s crash-and-burn performance at Wednesday’s presidential debate is just the latest in a long line of fundamental misjudgments that have left conservative mega-donors, casino magnate Sheldon Adelson chief among them, feeling burned by their fellow self-described billionaire.

According to a CNN report published Friday, Adelson has contributed up to $25 million in support of Trump’s candidacy, but recently has “bemoaned Trump’s lack of focus and what he sees as squandered opportunities.”

At one point, he promised $100 million to support Trump, according to the Wall Street Journal—the same amount the candidate himself has pledged he would donate to his campaign. Both men will likely fall far short of that number.

Fox Business reported that before Wednesday’s debate, Adelson had sent an email to Trump, telling him to stop attacking fellow Republicans like House Speaker Paul Ryan (R-WI), and to spend more time focusing on issues than complaining about media coverage. Though Trump has since quieted somewhat about his fellow Republicans, he continues to blame the national media for “rigging” the election.

One anonymous Adelson associate told Fox Business that Adelson had told him “Trump doesn’t listen to anyone—not even his family or Steve Bannon.” That associated added that Adelson told him he liked the Republican nominee “less and less.”

Fellow billionaire and conservative donor Foster Friess stayed mum to CNN on Adelson’s mood, saying he needed “to reserve what communication that took place private.”

Adelson, like many others who would normally dump tens of millions of dollars behind a presidential candidate promising the largest tax break in American history, has instead shifted his focus to the fight for protecting Republican majorities in Congress, according to the CNN report.

An Adelson spokesman did not respond to CNN’s requests for comment.

According to Federal Election Commission filings published Thursday, Trump spent more than $70 million in September, nearly matching his previous two months of spending combined. Hillary Clinton spent $83 million.