Read the Government policy on education and illness

'Each local authority shall make arrangements for the provision of suitable full-time or part-time education at schools or otherwise than at school for those children of compulsory school age, who by reason of illness, exclusion from school or otherwise, may not for any period receive suitable education unless such arrangements are made for them.'
(Section 298, Education Act 1993)

'The emphasis on securing a child's return to normal schooling applies equally to children with life threatening diseases and dying children, who also have a right to education suited to their age, ability, needs and health at the time.'
(DfEE Circular 12/94 para 18).

All schools and LEA'S must write a policy following this guidance.
We have written a model policy for schools and you can download it here