What is the ruling on praying behind an Imam who permits seeking help and intercession from Prophets and righteous Saints, and is he considered a disbeliever?

If the Imam permits tawassul (seeking intercession) regarding which there is a difference of opinion (such as by the right or status of someone), then prayer behind him is valid. However, if he permits supplicating to other than Allah and seeking aid from them, then this is major shirk (polytheism), and prayer behind someone who commits it is not permissible. He should be advised to clarify the matter to him. Sheikh Ibn Uthaymeen issued a fatwa that prayer behind an Imam who supplicates to other than Allah is invalid because he is guilty of major shirk. Sheikh Ibn Baz also issued a fatwa stating that prayer is not valid behind someone who associates partners with Allah, seeks aid from other than Him, or makes vows to other than Him, for he is a disbeliever and one should not pray behind him.