Trump and his people would now be smart, when ask, say "Khan who?",
But of course, the cannot.
Like Ron White being arrested for public intoxication, Trump and company may have the right to remain silent, but lack the ability to do so.
At most, Trump and the trolley dodgers should offer condolences to the son, stop, and move on to the next subject.
They just don't have the decorum or restraint to do this.