Until a person is mentally out, they are never out.
There are many who are inactive, disfellowshipped, and even some who disassociated, who were not mentally out. Like a boom-a-rang, they are apt to return.
I accidentally faded at one point and didn't even know it or have any concept of what fading is. But I still believe it was "the truth". I didn't want to be destroyed. So like a lamb putting his head in the lion's mouth, I came back and took steps to become active again, and went to the elder's about matters which ultimately got me disfellowshipped. This lead me to waking up mentally.