Kids always notice when another student in class is absent. So try building upon that. Even if you don’t know the reason for their absence, say, “I wonder why Alexis is not here today. Where do you think she is? Do you think maybe she’s sick? Is she visiting a friend or relative today? Will we miss Alexis today? What sorts of things will Alexis miss when she’s absent?”
 
Then follow it up with well wishes. As a group, have everyone close their eyes and picture Alexis. Have them wrap their arms around themselves (like they are giving themselves a hug) and then open their arms and send the hug out to the absent student. As they do this, have them say, “Alexis – we wish you well!”
 
When the student returns to class, make sure you let her know that she was missed and that everyone sent her well wishes!