Go To The Padlock Near At Boo And Feed Him Chocolate By Mixing This Food: 3 Chocolates.
And Bake It You Can Make "Giant Chocolate Bunny"

-If you want to FREE him, you have to pick the lock with mechanical skill=7 if you can't
find it, go to the left of Boo and you will see a giant lock.
- If you want to CURE him, you have to make him any food with chocolate. I will give you
two recipies:2chocolates and 1 flour or 3 chocolates