Jonah is portrayed as a smart but introverted child. When the family moves to the Ozarks, while at the motel , Jonah leaves just like his sister, but separately from her. When his mom tells the children that their father launders money Jonah does not have many questions. Notably asking his father multiple times though to confirm that he does do what Wendy said he does. At the end of My Dripping Sleep, Marty comes in to wish Jonah a good nights sleep, and after he leaves Jonah is seen opening his laptop which is playing clips of the horrible and graphic acts of violence the Navarro drug cartel commits.
Jonah applies many of the financial strategies his father taught him, including storing $5,000 of cartel money in offshore bank accounts after cleaning the funds via his high school homework service. Wendy suspects Jonah did this to prove his usefulness to his father.
Jonah described Buddy Dyker as his best friend and "only real friend [he] ever had". Jonah and Buddy were very close, often taking walks together. When Buddy is dying, he asks Jonah to read erotic literature out loud to him.
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