Complex sentence: The main character, Macon "Milkman" Dead III, derives his nickname from the fact that he was breastfed for far too long, and a passing neighbor happens to see him through the window, being breastfed by his mother.
Split into simpler sentences: The main character, Macon "Milkman" Dead III, derives his nickname from the fact that he was breastfed for far too long. A passing neighbor happens to see him through the window being breastfed by his mother.