This is the current big topic in the Wingnuttia, the question of how to silence a mother who lost a son in Bush's crazy wars and who now wants to talk to Bush about it.
The answer is to accuse her of everything under the sun: of selfishness, of arrogance, of dividing the country (!). This answer has worked so well in the past for the wingnuts, and there is no reason to change a recipe if it tastes good.
The nail that sticks up gets hammered down. This used to be a Japanese proverb, I think, but these days it describes the public sphere of the United States real well. So Sheehan is a nail and Michelle Malkin and the other wingnuts wield the hammer.