Yes, I do believe that Eric Trump is a liar for saying that his father has apologized to the Khan family. According to all of the media accounts, Donald Trump still has not apologized to the Khan family. It does not make sense to believe that Eric Trump would not lie for his father.
Let's be clear, Eric Trump knows full well that his dad did not apologize so he chose his words carefully. He said that by his dad saying that Mr. Khan's son was a patriot that that was his way of apologizing. I don't think Donald Trump has apologized to anyone the entire time Eric has been alive on the earth. This is the exact reason I say the kids are part of the problem because none of them have the honesty or care to pull their dad aside and counsel him on at least faking empathy.
Eric Trump is a liar for saying his father apologized to the Khan family. There have been multiple reports that this has not occurred. Donald Trump has had the opportunity to offer an apology, but has repeatedly defended his actions in public. Eric Trump's statement clearly do not reflect the reality.
While I don't know exactly what Eric Trump said in defense of his father Donald Trump regarding his comments about the Khan family, I believe that he will say anything to defend Donald Trump and ensure that his father is elected President. It isn't possible for Eric Trump to give an un-biased opinion or comment about his father, particularly during this election year. Unless the apology comes directly from Donald Trump himself, I wouldn't believe it.
You guys on the appropriate "left" side of this argument will sure believe anything you hear. Here are Eric's exact comments from the cnn story linked to this question: "I think that's a great question for him, and he has by calling them a hero,..."
Eric Trump wasn't stating a lie, he was expressing the opinion that from what he knows about his dad, calling the soldier a hero was his dad's way of apologizing in a sense. These are just character arguments against Trump the younger, since leftist media outlets are having a hard time finding bigger ways to blow this whole situation out of proportion.