Parangi's daughter, Lacey Te Whetu, and her on-again off-again partner, Shane Neil, have pleaded guilty to their role in his death.
Defence lawyer, Julie-Anne Kincaide, said no one disputed Isaiah's death was tragic but at the time he died he was not in Parangi's actual, legal care.
She pointed to evidence from a police interview in which Parangi said she had heard the infant crying in the house where he was with his parents.
The last time she'd seen him he'd been asleep in the family station wagon. In the interview she was adamant the car windows, doors and sun roof were open.
Ms Kincaide disputed the crown's claim Parangi had rushed inside to consume synthetic cannabis after buying it from her dealer in Kawerau. Her account was she'd put shopping away and done two loads of washing before taking a nap.
"The defence says Isaiah's Nanny was not acting in place of a parent, both his parents were there, that Isaiah was not in her actual care and there was no act or omission, no departure from the standard of care expected of a reasonable person," Ms Kincaide submitted.
- AAP