Ever heard of consumption? If you don't cough, that's what'll happen. Coughing means you're breathing and breathing is what you need since you're not a fish that breathes water from the side of you're face. My mum once said "...if the lungs hurt, that's bad so cough it up so it don't."

[He takes out the vodka and pours a little in her cup and then in his.]

That'll help with the pain.