Now he's also defending Republicans who have sparred with the GOP presidential nominee, particularly Arizona Sen. John McCain, who Khan says was a source of encouragement for him during his son's deployment. Khan's son, the late Army Capt. Humayun Khan, was killed by suicide bombers 12 years ago. But before Humayun was killed, his father sent him McCain's book, Why Courage Matters: The Way to a Braver Life.
"Senator McCain -- he's my hero," Khan told CNN in an interview
. "The last book my son read that I sent him was Senator McCain's book about courage: "Why Courage Matters." So for me to hear Donald Trump malign my hero -- my son's hero -- it is just mind-boggling."
Trump first criticized McCain last summer during a town hall in Iowa when he questioned whether McCain, a Vietnam War pilot who spent several years undergoing torture as a prisoner of war after his plane was shot down, should really be considered a hero.
"He's not a war hero," Trump said. "He was a war hero because he was captured. I like people who weren't captured."
After Trump responded to Khan's DNC speech last week, McCain released a statement condemning Trump's rhetoric about Khan family.
"In recent days, Donald Trump disparaged a fallen soldier's parents," said McCain. "He has suggested that the likes of their son should not be allowed in the United States -- to say nothing of entering its service. I cannot emphasize enough how deeply I disagree with Mr. Trump's statement. I hope Americans understand that the remarks do not represent the views of our Republican Party, its officers, or candidates."
Khan said that he was "not surprised" by Trump's negative reaction to his speech, in which he criticized Trump for calling to ban Muslim immigrants, questioned whether he had ever read the U.S. Constitution, and said, "You have sacrificed nothing and no one."
Trump responded by suggesting that Khan's wife, Ghazala Kahn, who stood on stage with him, was forbidden from speaking because of their Muslim faith.
The back and forth between Trump and the grieving Gold Star family has continued into this week, leading many Republicans to rebuke Trump.
"We have been watching him malign even the senior-most leaders of his own party," Khan said. "The lack of decency is just amazingly shocking at his part. His surrogates to do try to balance it. ... History will treat this kind of behavior very cruelly when these elections are over."