The boy who lost his father to the last worst pandemic in turn taught his sons to be “killers.” The underlying message, though: “Being a killer was really code for being invulnerable,” as Mary Trump put it in her recent book. “Going forward,” the niece of Donald Trump said of Fred Trump, “he refused to acknowledge or feel loss.” The family, in her recollection, never discussed Fred Trump’s father, or his death, or its cause. It was the lesson above all others that Fred Trump passed on to his children—foremost to his middle son, his preeminent heir, the boy who would become the 45th president of the United States.

A president who far more often than not has tried to ignore or downplay or wish away the most devastating global outbreak of illness since the one that ended the life of his grandfather. Who mostly has refused to so much as wear a mask as the spread of sickness has wreaked havoc. Who mocked his opponent during Tuesday’s debate for his face-covering diligence. Whose every word and gesture communicates his priorities to the nation he leads. And for whom any acknowledgment of vulnerability always has seemed to be tantamount in his mind to an impermissible admission of weakness.

“Weakness,” in the Trump family, Mary Trump wrote, “was perhaps the greatest sin of all.”

“Weakness,” Tony Schwartz, the co-author of The Art of the Deal, once told me, “is Trump’s greatest fear by far.”

Weakness, however, inhabits the absolute center of the most primal aspects of the long-arc engine of Trump. He knows, in the most deep-seated way, of the utter unavoidability of human vulnerability—anybody’s, everybody’s and, of course, his own. And yet Trump resolutely followed the mandate his father modeled to squelch any such concession. Fundamentally disparate but inextricably linked, these are two of the most essential and major motivators of Trump’s lifelong pattern of behavior. Now, with the news that Trump has tested positive for the virus that’s killed more than a million people, all of this has come to a perilous head.

The wee-hours shockwave of his diagnosis has exposed the fragility of his bravado. The man who’s trumpeted his genes and his blood and his virility while deriding his foes for low energy is now stricken and sequestered, cut off from the adoring supporters who stoke not just his political prospects but his needy psyche. He is 74 and obese, and already was facing a pending public reckoning—and the fear of being seen as anything other than strong in the end is precisely what has made him so weak.

His lengthy record of germaphobia, encapsulated by his well-documented hatred of the shaking of hands, often has been considered merely a bullet-point piece of his list of idiosyncrasies. But in fact it reflects his latent knowledge of the power of infection to wreak quick and terrible consequences. “Shaking hands, you catch colds, you catch the flu,” he said in 1999. “And who knows what else?” he said in 2004. “You don’t want to be a liability,” he said, getting perhaps unwittingly closer to the crux, in 2013. “You don’t want to become somebody’s patient.” Trump, according to Jack O’Donnell, a former Trump casino executive in Atlantic City, was “preoccupied by a fear of communicable disease.”

In spite of this, and probably in many ways because of it, Trump has spent his life attempting to project uncommon vigor and blind positivity—the exact opposite of this awareness of risk, dumb-luck dread and fate. “You can’t be scared,” he (actually, Tony Schwartz) wrote in The Art of the Deal in 1987. “Nothing scares me,” he told a reporter from Newsday in 1991. He’s repeated versions of these declarations ever since. It is also on the most elemental level what’s fueled over the last five-plus years his political ascent—calling America weak, calling his opponents weak, issuing again and again facile expressions of blunt, impervious strength.

And throughout this disastrous year, as a spreading, insidious pathogen has created for him ever-increasing jeopardy, political and otherwise, Trump time and time again has dismissed the advice of experts and flouted the public health rules and regulations of his own administration, from his toxic use of the word “hoax” to his flip talk of miracle cures to his reckless politicization of the best-practices wearing of masks to his delinquent staging of packed-crowd rallies from Charlotte to Tulsa to Nevada and back to North Carolina and Florida and Pennsylvania and Minnesota just the other night—by which point his close aide Hope Hicks already reportedly was beginning to exhibit symptoms.

“We’re rounding the corner,” he kept saying last month. “Doing great.”

“The end of the pandemic is in sight,” he said … hours before his test.

As a boy, Trump watched his father respond to the death of his father. As a man in his 30s, he watched the alcohol-exacerbated descent of his older brother as well as the AIDS-driven demise of his mentor, the infamous Roy Cohn—in both cases, though, keeping conspicuous, even callous distance from these distinct but marked and unmistakable reminders of human frailty. And as a man in his 40s and 50s, he watched the dominant, domineering Fred Trump, wracked by dementia, shrivel and wither away. Now, in the assessment of Schwartz, Donald Trump finally is being forced to grapple squarely with the plain reality of human vulnerability.

“This is the heart of it: This feeling that he cannot control his circumstance is overwhelming and unbearable to him, so he has built a life around avoiding that feeling, including by inventing a reality … a fictional world … a myth he’s made for himself that has almost no bearing on what’s actually going on,” Schwartz told me Friday.

“He is confronting his own mortality—here it is—and now it’s physical, it’s political, it’s mental, it’s emotional,” he said.

“On every count, weakness.”