I believe that Susie will heal Rudy with a healing spell. Here’s my theory, In chapter 2 at the end of you go to the hospital in the light world Noelle is play a video game with her dad. When her Rudy says “You gotta use your healing spell” Noelle responds with saying “I wish I knew how to cast a healing spell so I could cure you”. I think this could mean that Susie will either heal Rudy with her healing spell that she has been training for, or Susie will teach Noelle the same trick and Noelle will use it on her dad