She thought it was strange that he was naked, as his mother said he'd been in bed having a sleep.
The baby's mother, Lacey Te Whetu, told her she'd last seen him breathing two hours earlier when she'd put him down for that sleep. He'd recently had the flu.
When English first saw the baby an older woman and man were attempting CPR, and she later established the woman was Parangi. She and other paramedics were unable to revive him.
English said when the baby's mother was told her son was dead she cried out "come back to me my baby".
His father Shane Neil didn't appear to show any outward emotion.
Isaiah's parents pleaded guilty last month to their son's manslaughter.
Earlier in the day Parangi's next door neighbour, Sharon Biddle, said she saw Shane Neil sitting on the back doorstep and a station wagon parked in the Te Whetu's driveway with the windows up.
The Crown alleges baby Isaiah spent at least three hours in the car while his grandmother and mother binged on synthetic cannabis.
- New Zealand Newswire