Fever can support the immune system's attempt to gain advantage over infectious agents, such as viruses and bacteria, and it makes the body less favorable as a host for replicating viruses and bacteria, which are temperature sensitive. Infectious agents are not the only causes of fever, however.
Your sister's grandson is your great nephew. You are his great aunt (if you are a woman) or his great uncle (if you are a man).
The Princess Bride is a book by William Goldman under the pseudonym S. Morgenstern. In the film, the grandfather gives this book as a gift to his sick grandson and stays to read it to him. Map of Florin and Guilder.