As someone who gets really sleepy after a stressful or traumatic event/day i like to think that Kevin is the same and when things calm down he feels really drowsy and sleepy when all the adrenaline leaves and the full body shaking stops
jean having a "kevin look" is so real and true to me, a softening of eyes a small curve of lips a relaxed line of eyebrows an overall fondness! this expression is there even when he's talking to kevin on the phone even when he's bickering with kevin