Characterize the relationship between Nico and Fiona prior to Nico's death.

Nico and Fiona had been incredibly close prior to Nico's death from complications due to AIDS. At the age of 15, Nico's parents had kicked him out of the house. 11-year-old Fiona had then done her best to take over as Nico's mother, bringing money, food and allergy medicine to the house where Nico lived with several other young men. Nico's friends had eventually become Fiona's friends as well.