So I have had this thought festering in my head for the past little while, and while I doubt this theory, it gives us a discussion while we wait for Ghost Story. Now among all the beings we know of with interest in Harry, we need to think of those with both the ability and desire to prevent Harry from frying his brain. Of those, I submit the following:
Mab
Lasciel
Uriel
Ivy/The Archive
Okay, the easiest to eliminate from these beings is Uriel, because he is only allowed to interfere so much, and he gave Harry the ability to use Soulfire (presumably). If he did or did not is a discussion for another thread. So, strike Riel from the list of suspects.
The next suspect that I can eliminate us Ivy/ The Archive. Why would Ivy wan to help Harry? Affection, knowledge of him being needed in the future? Who knows. The ability to fix it would require an insane amount of power, which she has. The reason for that is that she is completely neutral, and an arbiter of The Accords. Thus, evn though Ivy would have the desire to help Harry, The Archive can presumably override Ivy, thus the suspect is eliminated.
Now I will try to eliminate Mab. The reason why I doubt that Mab would fix it is not because of her desire to have Harry as her Knight, but rather why would she? She is Mab, to her, a simple human is nothing, and she could easily allow Harry to blow up his mind, fix him, then say he owes her. Thus, it stands to reason that she could potentially benefit from Harry blowing up his mind.
Finally, that leaves Lasciel. This immortal being was bound in Harry's basement, less than ten feet from Little Chicago. I realize that she was bound within several circles, but she is a Denerian, and if there is any being in the Dresdenverese that is allowed to cheat, it would be one of them. This gives her the opportunity, and finally, the motive would be that a Fallen Angel must be voluntarily accepted by the mortal soul. If Harry cannot function or freely make the choice choice. If Harry is brain dead, then Lasciel can't take him over, furthermore, his death means that she is trapped for a pretty long time in the subbasement of a paranoid wizard with some pretty heavy wards protecting it.
Thoughts?