If the theory is true his family converted into Islam when he was four years old. Regardless of whether he has jewish blood he's been a radical anti-western, anti-Israel shia-muslim and served in the Revolutionary Guards militia his entire life.
The standard version of the story focuses on Hitler's paternal grandfather. Hitler's father's mother is said to have worked as a maid for a Jew and there were rumours that Hitler's father was actually the employer's biological child. No evidence for this has ever been found.
...
MOREOVER:
Ian Kershaw, "Hitler ...", Vol. 1, pp. 7-9 dismisses the story as nonsense. At the time when Hitler's grandmother worked as a servant in Graz for a family supposedly called Frankenberger (the 1830s) Jews were completely banned from living in Graz (and the whole province of Steiermark - Styria).
And just like this fact does not justify the inquisition and does not turn the jews into the villains of the inquisition from its victims, so does not the possibility that Ahmadinejew has jewish blood justify his anti-Israel/antisemitic views or implicate the jews in his despicable rhetoric and actions.
Does this make Mahmoud Ahmadinejad a possible mole for the Mossad?
(Hebrew: המוסד למודיעין ולתפקידים מיוחדים‎ - Institute for Intelligence and Special Operations)