[He knows it Grell, and for good or bad he trusts you as a friend. But for now he can't think of anything you could help him with and he doesn't want to worry you without need, thus he won't be talking, for now.]

I know, Grell-san.

But until I'm older enough to protect you, I suppose I'll have to content myself with fighting besides you if you need me and to avoid you little problems because of me, right?