Of course. Sebeos is a Christian. He tries to understand what happened and give, with some Arabic informations, (merchant, etc) is own explication of what happened.
Sebeos try to understand what happened with the Arabs. He states his own theory.
I can only say that this text bothers you as much as myself because we think Muhammad never existed.
The only personal touch of Sebeos in his text is when he says " Then all of them assembled together, from Havilah to Shur, which is opposite Egypt [The text is corrupt here. The citation is from Genesis 25.18 {Shur is the area inhabited by Ishmaelites immediately to the east of the Nile Delta bordering Sinai}, and they set out from the P’arhan desert {the Paran desert is the desert area stretching from Wadi Feiran (“Paran”) at the foot of Mount Serbal in western Sinai to Petra between the Dead Sea and the Gulf of Akaba in the east} [being] twelve tribes [moving] in the order [of precedence] of the Houses of the patriarchs of their tribe. They were divided into 12,000 men, of which the sons of Israel were in their own tribes, 1,000 to a tribe, to lead them to the country of Israel. They traveled army by army in the order [of precedence] of each patriarchy: Nebaioth, Kedar, Adbeel, Mibsam, Mishma, Dumah, Massa, Hadad, Tema, Jetur, Naphish and Kedemah [Genesis 25. 13-16]. These are the peoples of Ishmael.
He obviously here try and tie up the arabs rise with biblical story of Ishmael.
Reread the Quran. There is a covenant between one "Jewish" representative and one person which is an "Arab" one united in a common project.
Ishmael and Abraham building the house ?