He... doesn't really understand. She gets chest pains from staying indoors? Heart palpitations from all those ambient micro waves radiating off the appliances or some such superstition? Is she somehow even more claustrophobic than he is?

"Alright," is what he ends up saying, sounding unconvinced but not wanting to argue with how she feels. This is probably something they need to talk about without the language barrier.

"If you like, we can make food and go outside to have it," he offers. Maybe she'll feel more comfortable sitting on grass than at a dining table with all the unexplained, sometimes illogical social expectations that carries.