I wish we could do more for Flayn, but since we've got no leads, our only option is to search the monastery with a fine-tooth comb. Someone must know something.
Gather clues about Flayn by talking to different people throughout the monastery. If someone seems suspicious, you should check their room or other places they might spend time.
  1. Accept the quest from your house leader.
  2. Gather information about Flayn.
  3. Report to Claude.
Jeritza is suspicious, to say the least. I think you should ask him directly. He should be at the training grounds or in his quarters.