"Mohammed borrowed heavily from old Jewish legends and stories and incorporated these into the Koran. Alongside this, he changed a lot of the well known and accepted biblical stories to fit his self serving concepts of his position as the last and most important of all the prophets and messengers sent by God.
I do not believe he is representative of an Abrahamic faith simply because he believed this or that Islam is Abrahamic because one of the main components of Islam is to eliminate the two Abrahamic faiths---Judaism and Christianity---by any means necessary up to and including outright massive genocide. 
Also, his "theology" is centered on him and what he demands although it is well cloaked in religious words and pretensions.
Islam is more akin to a totalitarian intolerant violent ideology with a religious component than a theology that inspires its adherents to a heavenly lifestyle."