Owen Atkin, aged seven, was left in agony and so badly wounded he could be scarred for life, with medics unsure whether his hair will ever grow back fully.
A fundraising appeal has been launched to help the youngster, who is recovering in the burns unit at Sheffield Children's Hospital, and his family.
Owen's father Paul Atkin said his youngest son had been in someone else's care in Southey Green, Sheffield, when he was scalded at the weekend.
The 36-year-old Sheffield parks maintenance worker, who lives in Hoyland Common, Barnsley, with Owen and his elder brother Lewis, aged 10, and their stepmother Kirsty Vasey, said police and social services are investigating the circumstances.
"I rushed to hospital when I heard what had happened, and I found Owen in absolutely excruciating pain. His eyes were closed and he was shouting 'please don't let me die'," he said.
"It's the worst possible feeling as a father to be sat there helpless, knowing there's nothing you can do to take away the pain.
"He's normally fun, spirited and full of beans, but this has left him so upset and shocked, and in such great distress."
Mr Atkin added that Owen, who is a Sheffield Wednesday fan and loves penguins, had been 'up and down' during his time in hospital, where he is expected to remain into next week.
"One minute he'll be walking around and dancing and the next the pain will really hit him and he'll be throwing up," he said.
Owen, who is obsessed with planes, has received special messages sent to cheer him up from the Belgian Air Force F-16 solo display pilot Stephan 'Vador' Darte and the RAF Typhoon Display Team.
Sarah Roper has launched a fundraising appeal online, with a target of Â£500, to cover the family's costs and pay for a richly deserved holiday to reward Owen for his bravery and help him recover from the trauma.
Mr Atkin said it would 'mean the world' to Owen if he and the family could get away for a few days to help them relax and come to terms with what happened.
"Owen's been astoundingly brave. I don't think I would be coping so well if it was me. He deserves a treat after everything he's been through," he said.
"Just one night away at the seaside would mean the world to us."
A South Yorkshire Police spokeswoman said: "An investigation is currently ongoing into reports a seven-year-old boy had suffered serious burns following an incident at a property on Southey Green Road, Sheffield, on Sunday, May 27."
You can donate at www.gofundme.com/support-for-hospital-costs.