The inquest is considering the hospital's food-handling protocols for patients with food allergies, and how Louis was managed after he suffered a reaction.
Catan said she told emergency and medical staff about Louis' asthma, anaphylaxis and allergies to eggs, milk and nuts on his admission. He was kept overnight and she called in the morning for news on his condition.
The nurse told her he complained of the tingling, a clear sign to her he was having an allergic reaction. Catan said she learned from staff after his death he ate "no more than a spoonful" before complaining.
"They couldn't find out what caused the food reaction," she said.
Irene Fisher, who served Louis his breakfast, said the nurse looking after the teen told her about his allergies but didn't note it on the kitchen whiteboard, as per protocol. It was the obligation of the nurse caring for him to have filled in the whiteboard.
Fisher said Louis asked for three Weet-Bix, a glass of water and soy milk. She got the items, including the soy milk, from the fridge.
Someone at the hospital later asked her for the milk served to Louis and she gave them the open carton.
Helen Hutchins, the nurse in charge, agreed the absence of details about Louis' allergies on the whiteboard was a "failure of the system".
After Louis complained to Hutchins of tingling, she asked nurses to observe him and called for doctors. She knew he had allergies but was unaware he had anaphylaxis. Even so, only doctors were allowed to administer adrenaline.
Simon Tate said his son's death changed their lives and should never have happened.
"We continue to struggle every day with the emptiness, loss and circumstances," he said.
"He was in hospital, at a place where he should have been safe. Yet despite us providing clear and concise communications about his food allergies, he died.
"Our hope is this inquest not only provides us with the many answers we need and deserve, but that it closely examines food safety and anaphylaxis management protocols at Frankston Hospital."
