Capt. Humayun Khan (above) was a soldier who died while trying to protect his unit in 2014 in Iraq

Donald Trump reportedly had to ask what a Gold Star family was after he attacked the Muslim-American parents of the soldier who was killed while serving in Iraq.

Capt. Humayun Khan was a soldier who died while trying to protect his unit in 2014 in Iraq.

His parents, Khizr and Ghazala Khan, appeared during the Democratic National Convention in July after the Republican presidential candidate had unleashed a vicious attack against Muslims.

Khizr Khan paid homage to his son and held up his pocket-sized Constitution and said Trump has sacrificed 'nothing.'

The billionaire businessman responded to the powerful speech Khizr Khan gave at the convention by attacking and suggesting that Ghazala Khan was not allowed to speak on stage because she is a Muslim.

His parents, Khizr and Ghazala Khan (pictured together above), appeared during the Democratic National Convention in July after the Republican presidential candidate had unleashed a vicious attack against Muslims

Donald Trump (above) reportedly had to ask what a Gold Star family was after he attacked Khizr and Ghazala Khan ,the Muslim-American parents of Capt. Humayun Khan

However, she said she did not want to speak on stage because she was to upset and hurt.

When one of Trump's advisers warned him about how he had just attacked a Gold Star family, Trump responded 'what's that?', the New York Magazine reported on Saturday.

The term Gold Star family is often used to reference a family that lost a loved one while they were serving in war. Since 1936, the United States has officially recognized these families.

Trump's then campaign manager, Paul Manafort, reportedly had to explain to the GOP presidential candidate what 'Gold Star family' meant.

'The election is about the American people, it's not about you,' Manafort reportedly told Trump, while adding that Khizr Khan was not running for president.

Khizr Khan has campaigned for Clinton and even appeared in a touching ad for the Democratic presidential candidate.

On Thursday, he held back tears while speaking about how the Republican presidential nominee is peddling hate and no less than the 'future of the earth' is at stake in the November 8 election.

'There comes a time in an ordinary citizen's life where you have to gather all the courage you have and you stand up and speak against tyranny and speak against un-American hate,' Khan said in a reference to Trump's stance on immigration, which has ranged from a complete ban on foreign Muslim immigrants entering the United States to 'extreme' vetting and an ideological test for would-be immigrants from countries and regions plagued by extremism.

A senior adviser said Trump's son-in-law, Jared Kushner (above), is the 'final decision maker' for the campaign

'This hate,' he said at the Masjid William Salaam mosque, 'is un-American.'

Trump fired back with a familiar refrain, telling ABC News that Khizr Khan's son, who died in Iraq trying to protect his unit from a suicide bomber, would still be alive had Trump been president in 2004 instead of Republican George W. Bush.

'I wouldn't have been in Iraq,' Trump said, once again falsely insisting he was opposed to the Iraq War before it started. 'Had I been president, Capt. Khan would be alive today.'

Fumed Khizr Khan said, 'This is the most cruel thing you can say to grieving parents.'

The New York Magazine also reported that a senior adviser said Trump's son-in-law, Jared Kushner, is the 'final decision maker' for the campaign, as his wife, Ivanka, has 'exerted her influence' to put him in the position.

The adviser said Kushner's decision making is firm, unless when 'Trump is Trump.'

'Jared doesn't look at supporting the campaign as taking a philosophical position. He's opportunistic,' a Republican source close to the campaign said.