E: Mom?
Me: Yep?
E: Um, why did we give [Classmate] a ride home from school again today?
Me: Because her mommy doesn't drive.
E: Why?
Me: Because her mommy is sick, sweetie.
E: But she was sick last time.
Me: We'll be driving [Classmate] home every day, because her mommy is sick every day. She has a disease called MS that means her body doesn't work very well right now.
E: She's sick all the time?
Me: Yes.
E: That's... so sad, Mommy. (Starts crying.)
Me: You're right. It is sad. It is.