Ignis nods, dearly hoping that they can find someone to help them. But when Prompto says that he wants to stay here is what makes Ignis a bit worried. He doesn't want to sound as if he's coddling him, but he's seriously terrified what staying here would do Prompto's mental health. Staying in this tomb... even without his eyesight, the oppression, the rage this place wakes in Ignis cannot be good for Prompto at all.

And he hopes that Gladio will support him on this as well.

"I would stay if I didn't have to go as a Hand to the King. I'd like you to come with me, Prompto." He will be angry, Ignis can feel it, but he is seriously concerned for him.

"Driving is still impossible for me and I dare say Gladio is worse than you when it comes down to it." Ignis will dig out any and all excuses he can think of just to bring him along. They all need time to grieve but Prompto- he will never come to terms with this if he stays at the tomb, hoping something will change.