The peer support system was remodelled partly in response to added stresses crews face by attending more of "code purple" callouts, he said.
The system involves having crew members set up systems to recognise for themselves when they were struggling, and learn how to combat it.
A code purple call relates to when ambulance staff are notified of a person suffering cardiac or respiratory arrest and there is significant threat to their life.
When a 111 call is made for these patients, ambulance and fire staff are dispatched. If fire crews arrive first, they are able to give medical care to the patient until paramedics arrive.
For Mr Dudley, this work goes further. If paramedics are working on administering medicines, firefighters may assist with chest compressions, or look after the family members present.
"That will quite often fall to me or anyone from the crew to talk to the family, to get patient history, to tell them - despite what the outcome is - everything's going to be okay."
He might find himself making cups of tea with children, trying to keep them calm. Sometimes, the job involves indirectly warning family their loved one might not survive.
The number of these calls has increased since a memorandum of understanding between St John and the Fire Service was signed in 2014. In 2015, firefighters were called to 5793 code purple incidents. In 2016, they were called to 6024.
"For me, personally, the hardest thing is to deal with the family," Mr Dudley said. "Because the ambulance officer is too busy, they're administering drugs and doing their life-saving processes, I'm kind of left to manage the overall scene and deal with the family. It can be really hard.
"My process is talking about it with my peers ... I find that conversation is kind of enough."
The calls could sometimes add to existing stress, for example if a firefighter was having trouble at home or wasn't doing particularly well in work.
"You bring that to work, then all of a sudden at nine o'clock in the morning you're doing CPR on someone," he said.
There was evidence some people had left the job due to stress, but the struggles were made worth it by the knowledge more patients were surviving thanks to help from the Fire Service.
"In the long run, it's worth this little bit of pain that we sometimes have to deal with."