The ruling on praying behind an imam who goes to the graves of the awliya (close friends of Allah)

Question:
He says: Honorable Shaykh, may Allah grant you success. In one of the villages in Sudan, some people go to the graves of those they claim to be awliya (close friends of Allah) with the intention of seeking blessing and offering vows, and the imam of the mosque goes with them. When we discuss this with him, he says that he went out of courtesy and to win the people's affection. What is the ruling on praying behind this imam?

Answer:
Is it permissible for him to be courteous in shirk (associating partners with Allah)? It is not permissible for him to be courteous in shirk. It is obligatory for him to denounce it. This is the greatest of what is wrong. Whoever among you sees what is wrong, let him change it with his hand. The imam of the mosque going with them increases their evil, and they take him as an excuse before the people. One does not pray behind him. Yes, if we believed him and said that this was out of courtesy, but it does not appear to be courtesy; rather, he believes as they do. Yes.