Isn’t it rather obvious to all non-muslims that Muhammed was not a prophet of God?
Allah is not the God of Abraham.
What is already known to historians is that the 'final product' didn't show up until well after Mohammad's death (always convenient) in the time when the Meccan Arabs had assembled a large army and taken over a Byzantine city called Damascus.
At some point the Arab leadership decided they needed to "classy up" so they began assembling all the various pieces of Koranic materials ~ which included the Hadiths, or stories of the prophet as we know them, but which also included plenty of stories going back centuries.
This was a time when oral tradition was still highly respected and the handful of folks with perfect eidetic memory were well paid for their services. So, out came the stories and they were written down by Damascene scribes (a class of folks new to the desert Arabs) in something other than Arabic. More recent discoveries show that Aramaic, same as the language in Jesus day, was the original language. Written Arabic came later.
Some elements ~ including written material ~ possibly taken from a Torah recovered from somewhere in Arabia ~ were inserted where appropriate. This Biblical material sounded like it was from God, claimed to be inspired by God, so it must be of God ~ and there it was.
Now, a personal thought here ~ I've always thought it strange that when you get to this part the Torah materials are different than the standard but through time some of those differences have been demonstrated to be archaeologically accurate, so is it the standard version that errs, or the Damascus version that errs? The translators hired by the Arabs must have known something ~ so what was it they knew? Is that the real issue raised in the Koran and the Hadiths about ancient texts having been changed ~ not the charge that Christians had changed things, but an older tradition had?
Like to read his book to see what he thinks ~ probably have to buy it myself because the Paki holy men around here (5 mosques!) will piece this one out if it shows up at the library.
Anyway, leaving it to the readers, this is not unploughed ground. The operating thesis is that the Arabs pieced the Koran together in Damascus, then developed written Arabic over time ~ and finally transliterated the Aramaic text into Arabic.
That thesis differs from the claim that it is a perfect document handed down by God from Heaven.