“I said to my daughter, ‘Can you teach me to tweet, so I can tweet at the president and tell him he’s a liar?’” Mr Brooks told the newspaper.
“You know when you hear people lying, and you want to fight? That’s the way I feel last night. He’s a damn liar.”
Sergeant Brooks was killed during what was branded a “mishap” by the Army during a mortar fight against Isis. He was posthumously awarded the Bronze Star, Purple Heart, Meritorious Service Medal and Combat Action Badge.
Mr Brooks, from Brooklyn, New York City, called the President a “damn disgrace to the White House”.
“I’ve been here for 17 years. Presidents George Bush and Obama, none of them behaved like this guy. This guy is a damn lunatic,” he told New York Daily News.
Mr Brooks’ comments come after allegations the President told the widow of another fallen serviceman “he knew what he signed up for”.
He also tried to defend his record on contacting the families of dead soldiers by falsely accusing President Obama of failing to make phone calls to parents.
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Other grieving families have, however, weighed in to praise the 71-year-old for his response to US military deaths.
The father of Sergeant Cameron H Thomas, a US Army Ranger killed in April during a raid in Afghanistan, told The Washington Post: “He gave his condolences and made some comments how different his paperwork was when it went across his desk.”
“He said most of the paperwork he sees in these types of death says, ‘He’s respected by his peers.’ He said Cameron’s stuck out because it said he was respected and loved by his peers.”
He added: “Politics is politics, and maybe some people wouldn’t care to hear from him. But putting politics aside, it does mean a lot to a family, their child.”
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