He doesn't need to. Rubio pushed the story. the only ones pretending otherwise are the idiots at The Right Poop like NotSoSooperMexican.
Trump makes a threat, and the next day his minions release Heidi Cruz’s medical history. Trump makes a threat and his best friend “Peter” publishes a baseless hit piece in the Enquirer.
Trump is sleazy and can not control his temper.