Is it valid to pray behind one who permits seeking help from other than Allah?

Seeking assistance from other than Allah concerning the unseen or in matters that none but Allah can control is major shirk (polytheism) that expels its perpetrator from the fold of Islam after proof has been established against him, as indicated by the noble verses of the Quran and the prophetic traditions. Scholars unanimously agree on the invalidity of praying behind a disbeliever, because Islam is a condition for the validity of prayer, and worship is not accepted from a disbeliever. If the imam permits seeking assistance from other than Allah concerning the unseen or in matters that none but Allah can control, then proof must be established against him by citing texts. If he insists on his false doctrine, then it is not permissible to pray behind him. However, if he permits seeking assistance from other than Allah in a manner that does not fall under the category of major shirk, then praying behind him is permissible.