as salam alaikum
Alevism is a cultural-religious movement mainly based in present Turkey whose belief includes elements of Shiism, Tasawwuf and other ethnical rituals. It is difficult to dissect how exactly historically the movement came into existence; they themselves trace their origins back to Ali, peace be upon him, and the Imams after him. However certain facts have casted doubts to this claim like the followings:
1) The Imams of Ahl al-Bayt always said to be servants of Allah with no claim of divinity or to be God's incarnations of hypostatic nature. Some Alevi belief and literature suggests the contrary.
2) The Imams of Ahl al-Bayt always emphasized the shari'ah as the path of salvation and spiritual upliftment. Alevis however do not follow shari'ah.
3) The Imams of Ahl al-Bayt never performed certain practices that are customary in Alevi faith. Such rituals are considered innovations that Islam never brought.
Therefore despite the claim that Alevis are a sect of Shiism, their being de facto followers of the Ahl al-Bayt cannot be substantiated.
With prayers for your success