The 29-year-old suffered lung and kidney damage following a violent fit in 2001. Hetherston passed away at home in Coatbridge, Lanarkshire, on Saturday.
His brother, the former Raith and Albion Rovers manager, Peter, paid tribute. He said: "It has been well documented that he suffered from epilepsy. And he had a few bad turns, even on the football ground, and gave everyone a fright.
"He's had a few over the years but he came through them. Unfortunately he never got through this one.
"We are all devastated, this is a very difficult time for us.
"We'll remember him for the talented boy he was. He was at St Mirren and Raith Rovers.
"He could have made a successful career out of it but we have all just got to get through these hard times and get on with it."
After he was diagnosed with epilepsy in 1997, Hetherston, who was with St Mirren at the time, vowed to continue playing.
He had to stick to a strict regime of medication to keep the condition at bay.
Strathclyde Police said there were no suspicious circumstances and that a report would be sent to the procurator fiscal.