Yes he does. He has said bluntly that there was no Holocaust. Period.
He questions the 6 million JEWS figure, and the methods used to mass murder.
He's not really questioning anything. He denies the 6 million Jews figure and denies the existence of gas chambers. He's as convinced of the historical accuracy of his beliefs as most everyone else is convinced to the contrary. He's equally as convinced of the authenticity of "The Protocols of the Elders of Zion". So it's not really correct to portray him as an inquisitive skeptic. He's taken up a contrary position and is as closed to the idea that millions of Jews perished as everyone else is the idea that the Holocaust never happened.
That's not a sin (unless he knows the truth and is obstinately refusing to accept it) and it certainly doesn't deserve a criminal prosecution but it does raise questions about his judgment and common sense.