Here's some of the evidence given so far re degrees of sickness:
Nurse Lisa Shannon is up next in the witness box.
Ms Shannon had worked for five years at Korumburra Hospital, which had two beds in its urgent care centre.
The set-up at the hospital means one nurse cares for both patients.
Ms Shannon says at about 10am the day after the lunch, both Don and Gail presented to the urgent care and reported their symptoms.
"Donald was considerably sicker than Gail, on arrival," Ms Shannon says.
"I remained in the urgent care room, couldn't leave because I was quite busy with both of those patients."
She says she needed to assist Don to use the bathroom roughly every 10 minutes.
Don and Gail were both given IV fluids and an ECG was taken, as well as blood tests.
Don and Gail said they had taken an anti-nausea medication earlier that morning, Shannon says.
“They were requiring one-on-one care. They were very unwell,” Shannon says.
"It became obvious that Donald was becoming worse, he was very lethargic, blood pressure was going down a little bit, pulse was going up a little bit," Ms Shannon says.
She tells the court it was clear he was in a worse state than when he arrived.
Ms Shannon says Simon Patterson arrived to see his parents that morning, and she was aware that two other patients had arrived with similar symptoms.
When the results, of i-STAT blood tests returned, Ms Shannon says it was clear something out of the ordinary was occurring with Don.
"In regards to Donald, it was extremely abnormal," she says.
She tells the court that Don had a lactate of 6 [mmol/L], which was indicative of serious health issues such as sepsis or liver damage.
According to the Australian Commission on Safety and Quality in Health, normal lactate levels are less than 1.0 mmol/L in all age groups.
The reading would require transfer to a tertiary hospital with a larger ICU.