Before anything else, one has to recognize that the area of expertise for the respected author lies with respect to Quran interpretation.
Having said that, history is not exactly his forte, for the simple reason, of this quote from the work,
"Before we discuss the nomination of Yazeed as a successor to his father, it would be appropriate to understand some basic and relevant issues."
This violated, one of the conditions of the peace Treaty,
2: that Mu’awiya will not appoint or nominate anyone to the caliphate after him, but the choice will be left to the shur'a of the Muslims [1]
[1] S H M Jafri, Origins and Development of Shi'a Islam, 150, Oxford University Press