The FAA checkride said he was ready to be a CA. All the IOE check airman said he was ready to be CA. The FAA observed ride at the end of that IOE said he was ready to be a CA.

Now, you have flown and trained with him and think otherwise. You say others that have done those things with him would say otherwise as well. Maybe some of the items above will be/need to be scrutinized by the FAA.

Treat every flight as if your family was in the back.