In Islam, we believe that the Prophet Muhammad (peace be upon him) is the last and final messenger sent to mankind. I.e. there will be no new after him.
For anybody to believe in a Prophet after Muhammad (peace be upon him) they are considered out of the fold of Islam because this constitutes disbelief in the revelation of Allah which clearly states that Muhammad (peace be upon him) is the seal of the Prophets. This is a consensus amongst all Muslims.
With Ergun and Emir Caner claiming to be ex devout Sunni Muslims they would have believed the same thing. A Sunni Muslim usually means one who follows the Qur’an and Sunnah according to the pious predecessors, namely by adhering to a particular school of thought such as Hanafi, Sha’afi, Maliki, Hanbali or by taking all of these schools of thought into consideration and following what is the more correct opinion in terms of evidence from the authentic Ahadith. Whichever of these Ergun or Emir Caner supposedly were, the belief of Muhammad (peace be upon him) being the seal of the Prophets is the same.
You can see from the two clips above that Emir Caner says that Abd’al Wahhab was a Prophet.
what's the problem?
Along with the error of saying that 'Abd al Wahhab was a prophet, Emir also reiterated that “Wahhabi’s” are a sub-sect within the Sunni, so even though he acknowledged the "Wahhabi's" to be a sub-sect within the Sunni, he still went on to say that they believe 'Abd al Wahhaab to be a Prophet! How can that be when all "Sunni" Muslims believe Muhammad (peace be upon) to be the last and final messenger from Allah? It can't.
To go into further detail, Shaykh Muhammad ibn 'Abd al Wahhaab was a great scholar who called people to back to the pristine Islam without any innovations, even those of us who respect him highly and refer to his works, we do not, and never will see him as a Prophet.
So the question must be asked,
how comes Emir Caner the supposed ex devout Sunni Muslim does not understand that Muhammad (peace be upon him) is the last and final Messenger of God?
Once again the answer is simple – they are being untruthful and do not even understand the basics of Islam.
They desire to extinguish Allah's Light with their mouths, but Allah will perfect His Light, though the unbelievers hate it.