See http://www.bbc.co.uk/news/uk-england-28993791 .
As someone with experience of brain injury, I do hope they find this little boy very soon before his feed batteries run out. He is probably being fed by liquid feed into his tummy and the pump, if similar to the one I had, is usually mains powered but it has batteries that last maybe 24 hours.
UPDATE 1334z: It may be the family is in Marbella, Spain. I also read that they expect the tumour to regrow and it may then be inoperable. He may only have a few months to live. What a tragedy for all involved.
UPDATE 2125z: The little boy has been found in Spain.