"Is this possible? To just have all symptoms like that disappear? Or is she just being evasive because she doesn't want to do the work? "
Again, without having more context of history, it could be either spontaneous remission or fear of being committed. Minimally, getting into a primary physician or Emergency dept for a medical exam seems warranted here. She may have a serious medical condition that has gone into remission temporarily and it would be important to have it checked out, as just because the symptoms are no longer there doesn't mean the condition has gone away.