It’s a state court civil hearing, so Trump can’t pardon it. The president controls the federal government, not the state courts. Jones lost because he told the entire country that parents were lying about their kids being shot. The kids who were shot on national television and whose bodies were registered by the coroner and buried. It is in fact very hard to win a defamation law suit, because of our first amendment protections, but literally any surface level investigation at all would’ve easily proven the allegations as factually false. You’re right though, Trump absolutely would absolve Jones if he could.