Wow.

Has your wife ever consulted a conventional doctor or psychologist? From where do the "depression" and "anxiety" diagnoses come? Have you been able, without your wife, to discuss her symptoms with a professional? What do her parents think? Are her symptoms constant or do they swing rapidly or wildly?

In the end, it's up to her to accept help - which may or may not help.

How much damage is the whole situation doing to your daughter? What is the least harmful path for all of you involved?