Donald Trump “lives in fear” of suffering the same cognitive decline his father did, according to a brutal assessment by an MSNBC guest.

The Weekend: Primetime welcomed Timothy L. O’Brien, senior executive editor of Bloomberg Opinion, to discuss Trump’s musings about a third term in office.

The political analyst, speaking on the second installment of the show after its debut on Saturday, said the president’s motivation has always been either “self-aggrandizement” or “self-preservation.”

O’Brien added, however, that he doesn’t believe Trump will actually run again—even though he’d “love to live until he’s 300.”

“And I think he’d like to be president for 200 more years if he could,” O‘Brien quipped.

However, the 78-year-old’s vitality has visibly waned and he is acutely aware of his mortality, the panelist added. “As I was watching that clip, you know, one of the things that really struck me is, Donald Trump has aged,” he said.

Timothy L. O'Brien made the claims on “The Weekend: Primetime” on MSNBC. MSNBC

“When people talk about the things that are going to get in the way of a third term for Donald Trump, obviously, it’s voters. Obviously, it’s the 22nd Amendment. But he’s turning 79 in June.”

Despite Trump’s musings, the amendment prohibits anyone who has been elected twice from being elected again. Age and his family’s track record with brain disease should be his primary concern though, O’Brien suggested.

“He lives in fear of going down the path his father went down, which was dementia, followed by Alzheimer’s, into his 90s. And I think he’s carried that burden forever,” the journalist added.

Fred Trump, a real estate developer, died of both pneumonia and Alzheimer’s disease at age 93 in 1999. This was eight years after his first formal diagnosis of dementia.

He retained his title of chairman of the board of Trump Management even after the diagnosis. He also continued to come into work, according to family friend and business associate Richard Levy.

“He came in the office every day until the day he went to the hospital,” he said after Fred Trump’s passing.

Trump junior reportedly avoids talking about the touchy subject, partly because he bashed his predecessor Joe Biden for allegedly being cognitively impaired, but also because he fears this could be his fate too, O’Brien said.

Donald Trump and Fred Trump in the Trump Tower Atrium, 1987. Sonia Moskowitz/Getty Images

“Watching how he answers questions now compared to Trump 1.0, he slurs his words a little, he looks weary, he is slouched. And I don’t know how much authentic enthusiasm he has for the power and the office he holds, other than the fact that it keeps him out of jail and it keeps him center stage,” he added.

Donald Trump’s nephew Fred C. Trump III said last year that he fears a similar path for the president.

“Like anyone else, I’ve seen his decline. But I see it in parallel with the way my grandfather’s decline was,” Fred, 61, told People. “If anyone wants to believe that dementia did not run in the Trump family, it’s just not true.”