In HP: Prisoner of Azkaban, Professor Lupin gives Harry chocolate after every encounter with the Dementors/Boggart, saying "It helps, it really helps." Hermione says something along the lines of "That's how Lupin knew to give you the chocolate."
Why does Lupin give him chocolate? What does it "help"? How does it "help"?
I've been pondering this for some time now, and haven't come up with anything. :/
Thanks for your time! :)