The four year-old was told he would have permanent mental and physical problems after being diagnosed with a tumour the size of a golf ball when he was a baby.
But by copying the movements of his twin brother Kian, Finn has amazed doctors by making a remarkable recovery.
His parents, Claire Warriner, 41, and Pat Jordan, 41, from Hanwell, west London, were told to prepare for their son having severe damage after he developed meningitis following surgery to remove the tumour.
But, Claire said, "I think having a twin brother was probably one of the best physios he could have had.
"Kian and Finn are typical little boys and are extremely competitive with one another - they even see who can eat their breakfast the fastest!
"They have a very love/hate relationship too where they'll be picking on each other one minute and defending each other the next.
"But they love each other and the whole way through this, Kian has been encouraging Finn, saying 'Come on Finny, you can do it'."
Finn was also helped by a neurodevelopmental stimulation programme, which used repetitive exercises including colours and shapes to make him more aware of his surroundings.
Despite all his early injuries, Finn is now said to be developmentally equal to Kian in every area.