I think Allison is searching for that answer; maybe we will find it with her.
I can't tell exactly the nature of Will's search yet. I like the contrast of the two situations; one who cannot remember a thing about herself or the world, the other who keeps seeing more and more in everything they do. Neither seem like actual mental illnesses (if there is such a thing). They just can't handle the world around them and more importantly their self. The focus seems to be spiraling in on understanding just that. Is their response working in the direction that Dover Beach suggested, where they should be true to one another? As Will's father says, "You'd be better off if you were one of them...The ignorant armies that clash by night." That isn't really true, though. Maybe it means you wouldn't have tried to kill yourself and your son--but it also takes away the possibility of the search. It seems that a crucial part of Percy's search is having the questioner and the responder. It's like the Grand Inquisitor... As long as there is someone to target your questions to, to seek answers with, even the most miserable man is doing better than the everyday ignorant man.