Molly Vipond, 41, and 18-year-old Thomas went to Blackpool after a London-based businessman was so moved by their story he gave them a cheque for £5000.
The holiday brought back special memories of Molly’s other son Jeff, who died from cancer aged 16, a strain of which killed her father and is now affecting her and Thomas.
The mum, from the north of the city, said: “We first went [to Blackpool] in 2003 when Jeff was picking up and we were hospital-free at that point.
“This time we spent a lot of time going along the beach, going round the shops. It was nice, I could say to Thomas, ‘What would you like?’ We didn’t have to worry about a strict budget.”
Ms Vipond appeared in Channel 4’s Secret Millionaire on Sunday night, filmed earlier this year when millionaire insurance entrepreneur Ivan Massow made a week-long undercover visit to Pilton.
Moved by the work of three charities in the area he handed out a total of £91,500.
Groups were told he was featuring in a documentary about people changing their careers.
Ms Vipond, who is in regular contact with Mr Massow, also used the money to redecorate Thomas’s bedroom, and build decking and a gazebo in her back garden so she can enjoy a memorial garden she created to Jeff.
She said: “My pride and joy is my decking. We can go out and feel close to Jeff.”
Mr Massow – who kept his identity a secret until the end of his visit – also gave £50,000 to the children’s cancer charity CCLASP (Children with Cancer and Leukaemia Advice and Support for Parents).
It was founded by Valerie and Bill Simpson after their son Robert was diagnosed with leukaemia and it was through the charity he met Molly and Thomas.
Mrs Simpson said: “It’s a bit of a standing joke when you work in a charity, when people come in to be a volunteer you say, ‘You’re a Secret Millionaire . . .’.
“The second last day the crew said, ‘That’s it, we’re finished, he’s back down to London’. We were a bit like, ‘Oh . . . we were wrong’.”
However, when Mr Massow turned up the next day, their hearts leapt – but even then Valerie was stunned. “£50,000 – I was in shock,” she said.
Mr Massow also handed £15,000 to Fresh Start, which helps formerly homeless people settle in new homes, and £1500 to one of the charity’s users to buy carpet .