"They’re in a world of s***," one source close to them told the magazine.
"He may seem cool, but he’s sweating, and she’s like her father.
Mr Kushner had been phoning his associates to find out if the investigation would amount to anything.
While the couple are said to have insisted to friends they have settled in well after first year in Washington DC, they have apparently been unable to shake off concern about the investigation.
She works for his company in an office in Trump Tower while running her own successful clothing brand, and was a regular fixture by Mr Trump’s side on the campaign trail – often more so than his wife Melania.
It has been reported that as a teenager Ms Trump would sneak away from nights with friends to visit building sites with her father, and would often use her school lunch break to call him. She’ll take this company to great levels.”Now, that family business includes running the United States of America – something both Ms Trump and Mr Kushner have seemingly been preparing for their entire lives.
The couple follow the laws of the Sabbath, turning their phones off between Friday and Saturday nights to spend valuable family time with their children, Arabella, 5, Joseph, 3, and Theodore, eight months.
Mr Kushner was forced to defend his father-in-law in July this year when Mr Trump tweeted a photo of Hillary Clinton next to the Star of David with the caption: “Most corrupt candidate ever!
She’ll never acknowledge it and [will] blame the media.
But she’s been working on her reputation forever, and now it’s going to suffer horrifically. " Mr Mueller's investigators are reportedly turning their attention toward Donald Trump's son-in-law to look at what role he played in the firing of FBI director James Comey.
Mr Kushner has already turned over a number of documents voluntarily, which relate to any contact with Russia during both the campaign and transition period.
Mr Trump is said to be turning on Mr Kushner, who works as a White House political adviser.
At 35, he has a net worth of more than $US200 million.