I have two problems with what that old man is rambling.
One is him suspecting Mr. Lin to be using the Holy Moon Brain to shake the foundation of the church. But that operation was their idea. What is he on about?
The other is him saying: "the gods hiding in dream realms are imposters, only the Moon is the true God." (Paraphrased) Then he says later, that with some enigmatic means (implied to be connected to the Holy Moon Brain consumers), the Moon will be able to descend from the dream realm. This sounds like something a hypocrite would say.
I may have misunderstood some parts, judge my noticed points on your own.
-Darkness