Simon Says: I'm sick

Me:  Simon, go get your shoes.
Simon:  I can't, I'm sick.

Me (later):  Simon, it's time to brush your teeth.
Simon:  I can't, I'm sick.

Me (even later):  Simon, let's pick up these toys.
Simon:  I can't, I'm sick.

Simon:  When am I going with JoJo?
Me:  You can't, you're sick.
Simon (with enthusiasm):  I'm not sick anymore!

Edited to add: He's not sick of course.