The mainstream media has largely avoided coverage of Joe Biden’s health and fitness for office, but the question remains whether he possesses the physical and mental capacity to hold the most powerful office in the land, Donald Trump Jr. said Sunday.

"You see how draining this job is on people. I mean, Joe Biden refuses to campaign. He's not even doing Zoom calls. He's staying in his basement," the oldest Trump child told host told "Life, Liberty & Levin."

Trump wondered, "Is it that he can't do it or is it that he's just not physically able?"

CNN’S BRIAN STELTER CALLED OUT OVER ‘TONE-DEAF’ CRITICISM OF CONSERVATIVEMEDIA FOR QUESTIONING BIDEN’S MENTAL FITNESS

A series of high-profile gaffes and confusing statements by the presumptive Democratic nominee has resulted in some pundits questioning Biden's ability to run the country. In March, the far-left Young Turks said "everyone" was questioning Biden's fitness for office and the topic has since gained steam in conservative circles.

But CNN and other liberal media outlets have oddly downplayed or ignored the sensitive-but-crucial and they're not asking these kinds of questions about Biden, who has kept a low profile and struggled through a series of interviews and public appearances in recent weeks.

"I don't mean to make light of those health issues. I understand how serious that is. I know a lot of people that are older," Trump told Mark Levin.

"The difference is, we're not entrusting the average grandparents with the nuclear football mark. We're not entrusting them with the greatest economy of the world. We're not entrusting them with three hundred and fifty million people now."

HEALTH QUESTIONS FOR BIDEN OFF LIMITS WITH MEDIA

Trump Jr. called Biden's health record "pretty dismal," arguing that if "Donald Trump had a fraction of this, it would be a disqualifying factor as far as the media is concerned.

"They would talk about it nonstop," he said."Every television psychologist would be on TV saying that it's over."

Earlier this month, Fox News host Chris Wallace praised Biden's acceptance speech at the Democratic nomination for president as an "enormously effective" address that at the time, "blew a hole" in Trump's "mentally shot" characterization of the former vice president.

The presidency however requires more than just "delivering a teleprompter speech," Trump Jr. said.

"That's sort of his thing. After 50 years in D.C., you should be able to do that. But then you see, his wife almost had to carry him off the stage," he said.

" You know, is this guy going to wake up at 3 in the morning to take a phone call? Is this guy going to be capable of doing that? And if we're not sure, should someone other than me be asking this question?"

Biden himself agreed last year that “it's totally legitimate” for people to ask questions about his health if he decides to run for president, given his medical history -- which has included brain surgery in 1988.

JOE BIDEN'S MIND 'TOTALLY IN THE CLEAR DESPITE 1988 ANEURYSM' 

But Dr. Neal Kassell, the neurosurgeon who operated on Biden for an aneurysm three decades ago, told the Washington Examiner that Biden appears to be “totally in the clear” -- and even joked that the operation made Biden "better than how he was.”

"There's almost a zero percent chance that there's not a pretty significant effect on your ability to perform," Trump Jr. said.

"That doesn't mean you can't be a good guy. Doesn't mean you can't be a grandparent. It does probably mean we should question it. We should look into it, if you're going to be president of the United States and the media has refused to even touch it."

Fox News' Lukas Mikelionis contributed to this report.