Well obviously he did not write it, he was illiterate. The Koran was a collection of what he taught and claimed were revelations from God, and the Hadith were narrated by various sources about his life, but by all accounts the man could not read or write himself. Certainly he was an historical figure, which is sad, because he was a very blood thirsty awful person who founded a blood cult that has caused pain, death, and suffering for 14 centuries.
I don’t think you watched the video. The speaker provides evidence that mo not only didn’t write the koran but it’s not even based on his “teachings”.