While many boys are licking their pens as they prepare to write to Santa to ask for a Furby, an X-Box or Skylanders, Ronnie Harris only wants one thing: a cure for his dad's cancer.
Ten-year-old Ronnie said he'd be the 'happiest boy in the whole world' if Father Christmas could make his poignant dream come true.
He has told Santa he has just one wish this year - to make his father Russell Harris, 32, better, as he fights for his life.
His mum, Emma, 31, found the tear-jerking letter under her son's bed and burst into tears with pride.
This Christmas I would like one specific thing this year.
My dad has a really bad brain tuma.
Could you please find a cure for him to make him better and I will be the happiest boy in the whole world!
Emma, from Ipswich, Suffolk, said: "I didn't even know he had it. I was just cleaning Ronnie's bedroom when I found it shoved under his bed.
"I was very touched. It was heart-wrenching to think that a child of his age doesn't want anything for himself for Christmas.
"It made me cry. I felt so proud of him for thinking just of his dad and wanting him better."
Russell was struck down by a devastating brain tumour eight years ago. The malignant, inoperable growth has become more aggressive and is now classed as grade four severity, leaving him critically ill.
Mum-of-two Emma said: "The boys have good days and bad days. I care for Russell 24 hours a day and make sure my kids do everything they need to. Every day is absolutely normal. I still take them to school, I do everything a mother would do.
"But it's hard to see when he's badly sick a lot and they come out of their room.
"Ronnie does stuff 10-year-olds shouldn't have to do, like making his brother's breakfast and learning to cook.
"Ronnie has dealt so maturely with his dad's illness. He's called an ambulance when Russell has been very unwell and learned new skills to help around the house. He's even taking the cooking class in school so that he can cook his dad's dinner."