it's possible that he is dreaming of it and just doesn't know that he is. dreams aren't literal. (he could have dreams with Jill in them who is really Amy in disguise.)

maybe it's not working it's way into his dreams because he isn't thinking about it enough to make it a significant enough portion of his subconscious.

I know you have told him about some basic LDing stuff but make sure he knows that he can make this thing manifest in his lucid dreams.

Also, be sure to give him the link to DV.