Interested!

Comparing how big any dreams could be with the dream of emulating his older brother and cousin; this specific dream is bigger than any others that he could dream.

I think you caught it and the 'probably' means the strength of the AC is reduced. Almost all of these books will deteriorate, so if you take any given one of the books, it will probably deteriorate (completely). We can safely say it will deteriorate because according to the stimulus, "every kind of acidic paper gradually destroys itself", and there's no getting around that; deacidification will probably only happen to the significant books.