Joshua McCormack, from Rochdale, was diagnosed with a primitive neuroectodermal tumour (PNET) on his brain stem in October 2015.
He was deemed to be one of just 66 people in the world suffering from the deadly brain tumour.
Despite pulling through risky surgery to remove part of the tumour, chemotherapy and radiotherapy made him seriously ill.
Doctors revealed he would have to stop treatment, forcing his mother Nicola, 36, to launch a campaign to fund innovative treatment abroad.
But she was told that her efforts were too late and her son had just months left in September last year.
And earlier today she broke the devastating news on Facebook telling supporters that he had fallen into an 'eternal sleep'.
Her heartbreaking post read: 'Cancer I hope you are now truly satisfied: you have won, you were brutal, you were pure evil and unbelievably torturous to our beautiful Joshua's perfectly loving mind and body.
'Joshua's prolonged death was far from peaceful: it was painful, torturous, evil and horrific. Everything it shouldn't have been.
'You alone have successfully ripped a whole family apart leaving a massive void and an eternal feeling of emptiness and grief.
'So many plans, so much love, such a terrible waste of a perfectly planned life together.'