@Akabane : Initially they were going to lie to him about it, but when he mentioned the king being sick, she opted to stated it more defensively.
In that 'yeah, we don't plan to intentionally throw her into the fight, but the fight will probably come find her'
Obviously since they were the one who came here to find her, that's a lie, but the gramp still take that 'admission' as being good enough for him to let Fil go with them.