Little Matthew was rushed to hospital after he stopped breathing and collapsed at home in the east end of Glasgow.
His parents, Sylvain Schaeffer, 28, and Stacey McCuaig, 26, feared they might have lost him if it hadn't been for the experienced paramedics who first treated him.
Stacey said: "He collapsed on the sofa. Nobody knew what was going on, there were no warning signs.
"He stopped breathing and the ambulance crew were phoned and came out.
"Thankfully, the paramedic who was there had actually dealt with a diabetes case just a couple of weeks beforehand so he knew straightaway the first thing to do - he checked Matthew's bloods, and it was way too high.
"He said: 'He's diabetic', and they got him into hospital.
"We weren't present at the time, so we didn't know what was going on. We got a phone call to say: 'Get to the accident and emergency'.
"We rushed into accident and emergency, Matthew was in the resuscitation area at that point and I walked past his bed. I did not recognise my own son, he was that bad."
Matthew was diagnosed with Type 1 diabetes and will have to take insulin injections for the rest of his life to prevent organ damage.
He must also make sure that his blood glucose levels stay balanced by eating a healthy diet, taking regular exercise and having regular blood tests.
His parents admitted that dealing with the illness put a huge strain on them until charity Diabetes Scotland stepped in.
Matthew, now a healthy five-year-old, spotted volunteers collecting cash at a supermarket in Shettleston in June and the family was referred to Careline.
The confidential helpline for people affected by diabetes is staffed by professional counsellors who have extensive knowledge of the condition and who can provide information, take the time to talk things through and to explore emotional, social, psychological or practical difficulties.
Stacey said: "Diabetes Scotland has changed everything. It has given us a more positive outlook I think.
"Before we met them we were in such a dark place, and we felt like diabetes was controlling our lives, Matthew was isolated, he didn't have a lot of friends, he didn't understand.
"We were at that point of time where you go: 'Are we actually capable of doing this?'
"You've got someone you can go and turn to and say: 'What do I do? What are my next steps? What should I be doing?" I don't think there is any greater gift that we could have got at that time."
Sylvain and Stacey reveal their struggle in a YouTube video launched today by Diabetes Scotland to promote the charity's forthcoming fundraiser Walks for Diabetes.
Events will be held at Dean Castle, Kilmarnock, on August 24 and Strathclyde Country Park in Lanarkshire on September 14.
To find out more, visit diabetes.org.uk.