Ron is Mom’s boyfriend, whom she met in a grief support therapy group. Oskar initially dislikes the idea of Mom being with Ron, since it seems like she’s not grieving properly after Dad’s death. However, when Oskar finally learns a bit more about Ron—that Ron has lost his wife and daughter in a car accident—he softens towards him.
The timeline below shows where the character Ron appears in Extremely Loud and Incredibly Close. The colored dots and icons indicate which themes are associated with that appearance.
Chapter 3, “Googolplex”
...depicted it in different-colored beads. Oskar is upset that Mom has been spending time with Ron, her new boyfriend, but he buries his anger and instead makes Morse code jewelry out... (full context)
Chapter 7, Heavier Boots
Chapter 17, “Beautiful and True”