They do apply, but you don't seem to want to understand the argument.
Let's go with hysterical deafness instead.
This is a result of trauma. Someone becomes so intensely traumatized they actually lose their hearing (or sight, even). They will likely gain it back as they deal with the trauma and heal - but what they really need is a good therapist (ie. mentor) to help them deal with the trauma and put their shattered psyche back together.
The Exile spent nearly a decade actively not dealing with the trauma. In order to "hear" (use the Force again) the Exile is going to have to face things and try to mend, and a mentor can only help with that process.
The Exile needs to learn again how to feel and use the Force. As he or she does, and faces the past, and heals, he or she becomes even more powerful than the Exile was before the trauma. But in the interim, he or she needed a little boost - Kreia's bond with the Exile provided it.