What is said to a shaykh who prescribes adhkar (remembrances of God) for people and invites them to use them?

The ruling depends on the type of dhikr (remembrance of Allah) that the person enjoins. If it is mashrou‘ah (Islamically permissible and legislated), then he is to be thanked for guiding people to the Sunnah. However, if it is ghayr mashrou‘ah (not Islamically permissible) and not found in the Sunnah, then it is not permissible to obey him, and one must be wary of him.