Margaret Luxton, 59, was one of two women who died when a coach crashed near Looe in Cornwall in May 2014.
Coach driver Martin Chun was found guilty of causing death by dangerous driving and of causing serious injury by dangerous driving on Monday. He was jailed for five years.
The court had heard he was using a hands-free mobile when he crashed.
More on the campaign for tougher penalties, and other news from Devon and Cornwall
Mrs Luxton's son Terry, said: "We know now the driver was using his mobile phone and we need tougher legislation for drivers using mobile phones while driving - it should be as tough as drink driving."
While using a hands-free phone is legal, a driver can be still be penalised if they are distracted and not in control of their vehicle.
The Confederation of Passenger Transport UK said the penalty was the same as the penalty for using a mobile phone - a fine of Â£100 and three penalty points.
Anyone caught drink-driving or attempting to drink-drive can be subject to six months in prison, an unlimited fine and a driving ban for at least one year.
Mr Luxton said: "People use their mobile phones willy-nilly thinking 'yeah it's fine'. It's a distraction, if your eyes aren't 100% focussed on the road it is a distraction and you can kill people."
He added although it had been more than two years since the fatal accident, his mother's death was still affecting his father very badly.
"He's suffering from depression, anxiety and he's really not in a good place," he said.
The son of a coach crash victim has called for tougher penalties for people who use mobile phones while driving.